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Author SHA1 Message Date
Beman Dawes c97ad81672 Release 1.41.0
[SVN r57747]
2009-11-18 14:58:26 +00:00
209 changed files with 15111 additions and 38609 deletions
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# Copyright 2016, 2017 Peter Dimov
# Copyright 2017 - 2019 James E. King III
# Copyright 2019 - 2021 Alexander Grund
# Distributed under the Boost Software License, Version 1.0.
# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
version: 1.0.{build}-{branch}
shallow_clone: true
branches:
only:
- master
- develop
- /bugfix\/.*/
- /feature\/.*/
- /fix\/.*/
- /pr\/.*/
matrix:
fast_finish: false
# Adding MAYFAIL to any matrix job allows it to fail but the build stays green:
allow_failures:
- MAYFAIL: true
environment:
global:
B2_CI_VERSION: 1
GIT_FETCH_JOBS: 4
B2_ADDRESS_MODEL: 32,64
B2_VARIANT: debug,release
matrix:
- FLAVOR: Visual Studio 2008, 2010, 2012
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
B2_TOOLSET: msvc-9.0,msvc-10.0,msvc-11.0
B2_ADDRESS_MODEL: 32 # No 64bit support
- FLAVOR: Visual Studio 2013, 2015
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
B2_TOOLSET: msvc-12.0,msvc-14.0
- FLAVOR: Visual Studio 2017
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
B2_CXXSTD: 14,17,latest
B2_TOOLSET: msvc-14.1
- FLAVOR: cygwin (32-bit)
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
ADDPATH: C:\cygwin\bin;
B2_ADDRESS_MODEL: 32
B2_CXXSTD: 03,11,14,1z
B2_TOOLSET: gcc
- FLAVOR: cygwin (64-bit)
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
ADDPATH: C:\cygwin64\bin;
B2_ADDRESS_MODEL: 64
B2_CXXSTD: 03,11,14,1z
B2_TOOLSET: gcc
- FLAVOR: cygwin (64-bit, latest)
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
ADDPATH: C:\cygwin64\bin;
B2_ADDRESS_MODEL: 64
B2_CXXSTD: 03,11
B2_TOOLSET: gcc
B2_FLAGS: "include=libs/unordered/test/unordered include=libs/unordered/test/exception"
- FLAVOR: cygwin (64-bit, latest)
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
ADDPATH: C:\cygwin64\bin;
B2_ADDRESS_MODEL: 64
B2_CXXSTD: 14,1z
B2_TOOLSET: gcc
B2_FLAGS: "include=libs/unordered/test/unordered include=libs/unordered/test/exception"
- FLAVOR: mingw-w64, 32 bit
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
ADDPATH: C:\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\bin;
B2_CXXSTD: 03,11,14,17,2a
B2_TOOLSET: gcc
B2_ADDRESS_MODEL: 32
- FLAVOR: mingw-w64, 64 bit
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
ADDPATH: C:\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin;
B2_CXXSTD: 03,11,14
B2_TOOLSET: gcc
B2_ADDRESS_MODEL: 64
- FLAVOR: mingw-w64, 64 bit
APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
ADDPATH: C:\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin;
B2_CXXSTD: 17,2a
B2_TOOLSET: gcc
B2_ADDRESS_MODEL: 64
#- FLAVOR: CodeCov (VS 2019)
# APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
# B2_CXXFLAGS: -permissive-
# B2_CXXSTD: 14
# B2_TOOLSET: msvc-14.2
# COVERAGE: true
install:
- git clone --depth 1 https://github.com/boostorg/boost-ci.git C:\boost-ci-cloned
# Copy ci folder if not testing Boost.CI
- if NOT "%APPVEYOR_PROJECT_NAME%" == "boost-ci" xcopy /s /e /q /i /y C:\boost-ci-cloned\ci .\ci
- rmdir /s /q C:\boost-ci-cloned
- ci\appveyor\install.bat
build: off
test_script: ci\build.bat
for:
# CodeCov coverage build
- matrix:
only: [COVERAGE: true]
test_script: [ps: ci\codecov.ps1]
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@@ -1,23 +0,0 @@
# Copyright 2019 - 2021 Alexander Grund
# Distributed under the Boost Software License, Version 1.0.
# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
#
# Sample codecov configuration file. Edit as required
codecov:
max_report_age: off
require_ci_to_pass: yes
notify:
# Increase this if you have multiple coverage collection jobs
after_n_builds: 1
wait_for_ci: yes
# Change how pull request comments look
comment:
layout: "reach,diff,flags,files,footer"
# Ignore specific files or folders. Glob patterns are supported.
# See https://docs.codecov.com/docs/ignoring-paths
ignore:
- extra/**/*
# - test/**/*
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@@ -1,184 +0,0 @@
# Copyright 2022 Peter Dimov
# Distributed under the Boost Software License, Version 1.0.
# https://www.boost.org/LICENSE_1_0.txt
local library = "unordered";
local triggers =
{
branch: [ "master", "develop", "feature/*", "bugfix/*" ]
};
local ubsan = { UBSAN: '1', UBSAN_OPTIONS: 'print_stacktrace=1' };
local asan = { ASAN: '1' };
local linux_pipeline(name, image, environment, packages = "", sources = [], arch = "amd64") =
{
name: name,
kind: "pipeline",
type: "docker",
trigger: triggers,
platform:
{
os: "linux",
arch: arch
},
steps:
[
{
name: "everything",
image: image,
environment: environment,
commands:
[
'set -e',
'uname -a',
'wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -',
] +
(if sources != [] then [ ('apt-add-repository "' + source + '"') for source in sources ] else []) +
(if packages != "" then [ 'apt-get update', 'apt-get -y install ' + packages ] else []) +
[
'export LIBRARY=' + library,
'./.drone/drone.sh',
]
}
]
};
local macos_pipeline(name, environment, xcode_version = "12.2", osx_version = "catalina", arch = "amd64") =
{
name: name,
kind: "pipeline",
type: "exec",
trigger: triggers,
platform: {
"os": "darwin",
"arch": arch
},
node: {
"os": osx_version
},
steps: [
{
name: "everything",
environment: environment + { "DEVELOPER_DIR": "/Applications/Xcode-" + xcode_version + ".app/Contents/Developer" },
commands:
[
'uname -a',
'export LIBRARY=' + library,
'./.drone/drone.sh',
]
}
]
};
local windows_pipeline(name, image, environment, arch = "amd64") =
{
name: name,
kind: "pipeline",
type: "docker",
trigger: triggers,
platform:
{
os: "windows",
arch: arch
},
"steps":
[
{
name: "everything",
image: image,
environment: environment,
commands:
[
'echo $env:DRONE_STAGE_MACHINE',
'cmd /C .drone\\\\drone.bat ' + library,
]
}
]
};
[
linux_pipeline(
"Linux 14.04 GCC 4.4 32/64",
"cppalliance/droneubuntu1404:1",
{ TOOLSET: 'gcc', COMPILER: 'g++-4.4', CXXSTD: '98,0x', ADDRMD: '32,64' },
"g++-4.4-multilib",
[ "ppa:ubuntu-toolchain-r/test" ],
),
linux_pipeline(
"Linux 14.04 GCC 4.6 32/64",
"cppalliance/droneubuntu1404:1",
{ TOOLSET: 'gcc', COMPILER: 'g++-4.6', CXXSTD: '98,0x', ADDRMD: '32,64' },
"g++-4.6-multilib",
[ "ppa:ubuntu-toolchain-r/test" ],
),
linux_pipeline(
"Linux 14.04 GCC 4.7 32/64",
"cppalliance/droneubuntu1404:1",
{ TOOLSET: 'gcc', COMPILER: 'g++-4.7', CXXSTD: '98,0x', ADDRMD: '32,64' },
"g++-4.7-multilib",
[ "ppa:ubuntu-toolchain-r/test" ],
),
linux_pipeline(
"Linux 14.04 GCC 4.8* 32/64",
"cppalliance/droneubuntu1404:1",
{ TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11', ADDRMD: '32,64' },
),
linux_pipeline(
"Linux 14.04 GCC 4.9 32/64",
"cppalliance/droneubuntu1404:1",
{ TOOLSET: 'gcc', COMPILER: 'g++-4.9', CXXSTD: '03,11', ADDRMD: '32,64' },
"g++-4.9-multilib",
[ "ppa:ubuntu-toolchain-r/test" ],
),
linux_pipeline(
"Linux 20.04 GCC 9* ARM64 32",
"cppalliance/droneubuntu2004:multiarch",
{ TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '32' },
arch="arm64",
),
linux_pipeline(
"Linux 20.04 GCC 9* ARM64 64",
"cppalliance/droneubuntu2004:multiarch",
{ TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '64' },
arch="arm64",
),
linux_pipeline(
"Linux 20.04 GCC 9* S390x 32",
"cppalliance/droneubuntu2004:multiarch",
{ TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '32' },
arch="s390x",
),
linux_pipeline(
"Linux 20.04 GCC 9* S390x 64",
"cppalliance/droneubuntu2004:multiarch",
{ TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '03,11,14,17,2a', ADDRMD: '64' },
arch="s390x",
),
macos_pipeline(
"MacOS 10.15 Xcode 12.2 UBSAN",
{ TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' } + ubsan,
),
macos_pipeline(
"MacOS 12.4 Xcode 13.4.1 ASAN",
{ TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' } + asan,
xcode_version = "13.4.1", osx_version = "monterey",
),
windows_pipeline(
"Windows VS2017 msvc-14.1",
"cppalliance/dronevs2017",
{ TOOLSET: 'msvc-14.1', CXXSTD: '14,17,latest' },
),
]
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@REM Copyright 2022 Peter Dimov
@REM Distributed under the Boost Software License, Version 1.0.
@REM https://www.boost.org/LICENSE_1_0.txt
@ECHO ON
set LIBRARY=%1
set DRONE_BUILD_DIR=%CD%
set BOOST_BRANCH=develop
if "%DRONE_BRANCH%" == "master" set BOOST_BRANCH=master
cd ..
git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
cd boost-root
git submodule update --init tools/boostdep
xcopy /s /e /q %DRONE_BUILD_DIR% libs\%LIBRARY%\
python tools/boostdep/depinst/depinst.py %LIBRARY%
cmd /c bootstrap
b2 -d0 headers
if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
b2 -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker
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@@ -1,25 +0,0 @@
#!/bin/bash
# Copyright 2022 Peter Dimov
# Distributed under the Boost Software License, Version 1.0.
# https://www.boost.org/LICENSE_1_0.txt
set -ex
export PATH=~/.local/bin:/usr/local/bin:$PATH
DRONE_BUILD_DIR=$(pwd)
BOOST_BRANCH=develop
if [ "$DRONE_BRANCH" = "master" ]; then BOOST_BRANCH=master; fi
cd ..
git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
cd boost-root
git submodule update --init tools/boostdep
cp -r $DRONE_BUILD_DIR/* libs/$LIBRARY
python tools/boostdep/depinst/depinst.py $LIBRARY
./bootstrap.sh
./b2 -d0 headers
echo "using $TOOLSET : : $COMPILER ;" > ~/user-config.jam
./b2 -j3 libs/$LIBRARY/test toolset=$TOOLSET cxxstd=$CXXSTD variant=debug,release ${ADDRMD:+address-model=$ADDRMD} ${UBSAN:+undefined-sanitizer=norecover debug-symbols=on} ${ASAN:+address-sanitizer=norecover debug-symbols=on} ${LINKFLAGS:+linkflags=$LINKFLAGS}
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@@ -1,7 +0,0 @@
[*]
end_of_line = lf
insert_final_newline = true
indent_style = space
[*.?pp]
indent_size = 2
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@@ -1,397 +0,0 @@
# Copyright 2020-2021 Peter Dimov
# Copyright 2021 Andrey Semashev
# Copyright 2021 Alexander Grund
# Copyright 2022 James E. King III
#
# Distributed under the Boost Software License, Version 1.0.
# (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
---
name: CI
on:
pull_request:
push:
branches:
- master
- develop
- bugfix/**
- feature/**
- fix/**
- pr/**
concurrency:
group: ${{format('{0}:{1}', github.repository, github.ref)}}
cancel-in-progress: true
env:
GIT_FETCH_JOBS: 8
NET_RETRY_COUNT: 5
B2_CI_VERSION: 1
B2_VARIANT: debug,release
LCOV_BRANCH_COVERAGE: 0
CODECOV_NAME: Github Actions
jobs:
posix:
defaults:
run:
shell: bash
strategy:
fail-fast: false
matrix:
include:
# Linux, gcc
- { compiler: gcc-4.8, cxxstd: '03,11', os: ubuntu-18.04, install: 'g++-4.8-multilib', address-model: '32,64' }
- { compiler: gcc-4.9, cxxstd: '03,11', os: ubuntu-20.04, container: 'ubuntu:16.04' }
- { compiler: gcc-5, cxxstd: '03,11,14,1z', os: ubuntu-18.04, install: 'g++-5-multilib', address-model: '32,64' }
- { compiler: gcc-6, cxxstd: '03,11,14,17', os: ubuntu-18.04, install: 'g++-6-multilib', address-model: '32,64' }
- { compiler: gcc-7, cxxstd: '03,11,14,17', os: ubuntu-18.04, install: 'g++-7-multilib', address-model: '32,64' }
- { compiler: gcc-8, cxxstd: '03,11,14,17,2a', os: ubuntu-18.04, install: 'g++-8-multilib', address-model: '32,64' }
- { compiler: gcc-9, cxxstd: '03,11,14,17,2a', os: ubuntu-18.04, install: 'g++-9-multilib', address-model: '32,64' }
- { compiler: gcc-10, cxxstd: '03,11,14,17,20', os: ubuntu-20.04, install: 'g++-10-multilib', address-model: '32,64' }
- { compiler: gcc-11, cxxstd: '03,11,14,17,20', os: ubuntu-20.04, install: 'g++-11-multilib', address-model: '32,64' }
- { compiler: gcc-12, cxxstd: '03,11,14,17,20', os: ubuntu-22.04, install: 'g++-12-multilib', address-model: '32,64' }
- { name: GCC w/ sanitizers, sanitize: yes,
compiler: gcc-12, cxxstd: '03,11,14,17,20', os: ubuntu-22.04 }
- { name: Collect coverage, coverage: yes,
compiler: gcc-8, cxxstd: '03,11', os: ubuntu-20.04, install: 'g++-8-multilib', address-model: '32,64' }
# Linux, clang
- { compiler: clang-3.7, cxxstd: '03,11,14', os: ubuntu-20.04, container: 'ubuntu:16.04' }
- { compiler: clang-3.8, cxxstd: '03,11,14', os: ubuntu-20.04, container: 'ubuntu:16.04' }
- { compiler: clang-3.9, cxxstd: '03,11,14', os: ubuntu-18.04 }
- { compiler: clang-4.0, cxxstd: '03,11,14', os: ubuntu-18.04 }
- { compiler: clang-5.0, cxxstd: '03,11,14,1z', os: ubuntu-18.04 }
- { compiler: clang-6.0, cxxstd: '03,11,14,17', os: ubuntu-18.04 }
- { compiler: clang-7, cxxstd: '03,11,14,17', os: ubuntu-18.04 }
- { compiler: clang-8, cxxstd: '03,11,14,17', os: ubuntu-18.04 }
- { compiler: clang-9, cxxstd: '03,11,14,17,2a', os: ubuntu-20.04 }
- { compiler: clang-10, cxxstd: '03,11,14,17,20', os: ubuntu-20.04 }
- { compiler: clang-11, cxxstd: '03,11,14,17,20', os: ubuntu-20.04 }
- { compiler: clang-12, cxxstd: '03,11,14,17,20', os: ubuntu-20.04 }
- { compiler: clang-13, cxxstd: '03,11,14,17,20', os: ubuntu-22.04 }
- { compiler: clang-14, cxxstd: '03,11,14,17,20', os: ubuntu-22.04 }
# libc++
- { compiler: clang-6.0, cxxstd: '03,11,14', os: ubuntu-18.04, stdlib: libc++, install: 'clang-6.0 libc++-dev libc++abi-dev' }
- { compiler: clang-12, cxxstd: '03,11,14,17,20', os: ubuntu-20.04, stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev' }
- { name: Clang w/ sanitizers, sanitize: yes,
compiler: clang-12, cxxstd: '03,11,14,17,20', os: ubuntu-20.04, stdlib: libc++, install: 'clang-12 libc++-12-dev libc++abi-12-dev' }
# OSX, clang
- { compiler: clang, cxxstd: '03,11,14,17,2a', os: macos-11, sanitize: yes }
timeout-minutes: 120
runs-on: ${{matrix.os}}
container: ${{matrix.container}}
env: {B2_USE_CCACHE: 1}
steps:
- name: Setup environment
run: |
if [ -f "/etc/debian_version" ]; then
echo "DEBIAN_FRONTEND=noninteractive" >> $GITHUB_ENV
export DEBIAN_FRONTEND=noninteractive
fi
if [ -n "${{matrix.container}}" ] && [ -f "/etc/debian_version" ]; then
apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y sudo software-properties-common
# Need (newer) git, and the older Ubuntu container may require requesting the key manually using port 80
apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys E1DD270288B4E6030699E45FA1715D88E1DF1F24
for i in {1..${NET_RETRY_COUNT:-3}}; do sudo -E add-apt-repository -y ppa:git-core/ppa && break || sleep 10; done
apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y g++ python libpython-dev git
fi
# For jobs not compatible with ccache, use "ccache: no" in the matrix
if [[ "${{ matrix.ccache }}" == "no" ]]; then
echo "B2_USE_CCACHE=0" >> $GITHUB_ENV
fi
git config --global pack.threads 0
- uses: actions/checkout@v3
with:
# For coverage builds fetch the whole history, else only 1 commit using a 'fake ternary'
fetch-depth: ${{ matrix.coverage && '0' || '1' }}
- name: Cache ccache
uses: actions/cache@v3
if: env.B2_USE_CCACHE
with:
path: ~/.ccache
key: ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}-${{github.sha}}
restore-keys: ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}-
- name: Fetch Boost.CI
uses: actions/checkout@v3
with:
repository: boostorg/boost-ci
ref: master
path: boost-ci-cloned
- name: Get CI scripts folder
run: |
# Copy ci folder if not testing Boost.CI
[[ "$GITHUB_REPOSITORY" =~ "boost-ci" ]] || cp -r boost-ci-cloned/ci .
rm -rf boost-ci-cloned
- name: Install packages
if: startsWith(matrix.os, 'ubuntu')
run: |
SOURCE_KEYS=(${{join(matrix.source_keys, ' ')}})
SOURCES=(${{join(matrix.sources, ' ')}})
# Add this by default
SOURCES+=(ppa:ubuntu-toolchain-r/test)
for key in "${SOURCE_KEYS[@]}"; do
for i in {1..$NET_RETRY_COUNT}; do
wget -O - "$key" | sudo apt-key add - && break || sleep 10
done
done
for source in "${SOURCES[@]}"; do
for i in {1..$NET_RETRY_COUNT}; do
sudo add-apt-repository $source && break || sleep 10
done
done
sudo apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
if [[ -z "${{matrix.install}}" ]]; then
pkgs="${{matrix.compiler}}"
pkgs="${pkgs/gcc-/g++-}"
else
pkgs="${{matrix.install}}"
fi
sudo apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y $pkgs
- name: Setup GCC Toolchain
if: matrix.gcc_toolchain
run: |
GCC_TOOLCHAIN_ROOT="$HOME/gcc-toolchain"
echo "GCC_TOOLCHAIN_ROOT=$GCC_TOOLCHAIN_ROOT" >> $GITHUB_ENV
MULTIARCH_TRIPLET="$(dpkg-architecture -qDEB_HOST_MULTIARCH)"
mkdir -p "$GCC_TOOLCHAIN_ROOT"
ln -s /usr/include "$GCC_TOOLCHAIN_ROOT/include"
ln -s /usr/bin "$GCC_TOOLCHAIN_ROOT/bin"
mkdir -p "$GCC_TOOLCHAIN_ROOT/lib/gcc/$MULTIARCH_TRIPLET"
ln -s "/usr/lib/gcc/$MULTIARCH_TRIPLET/${{matrix.gcc_toolchain}}" "$GCC_TOOLCHAIN_ROOT/lib/gcc/$MULTIARCH_TRIPLET/${{matrix.gcc_toolchain}}"
- name: Setup multiarch
if: matrix.multiarch
run: |
sudo apt-get install --no-install-recommends -y binfmt-support qemu-user-static
sudo docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
git clone https://github.com/jeking3/bdde.git
echo "$(pwd)/bdde/bin/linux" >> ${GITHUB_PATH}
echo "BDDE_DISTRO=${{ matrix.distro }}" >> ${GITHUB_ENV}
echo "BDDE_EDITION=${{ matrix.edition }}" >> ${GITHUB_ENV}
echo "BDDE_ARCH=${{ matrix.arch }}" >> ${GITHUB_ENV}
echo "B2_WRAPPER=bdde" >> ${GITHUB_ENV}
- name: Setup Boost
env:
B2_ADDRESS_MODEL: ${{matrix.address-model}}
B2_COMPILER: ${{matrix.compiler}}
B2_CXXSTD: ${{matrix.cxxstd}}
B2_SANITIZE: ${{matrix.sanitize}}
B2_STDLIB: ${{matrix.stdlib}}
# More entries can be added in the same way, see the B2_ARGS assignment in ci/enforce.sh for the possible keys.
# B2_DEFINES: ${{matrix.defines}}
# Variables set here (to non-empty) will override the top-level environment variables, e.g.
# B2_VARIANT: ${{matrix.variant}}
run: source ci/github/install.sh
- name: Setup coverage collection
if: matrix.coverage
run: ci/github/codecov.sh "setup"
- name: Run tests
if: '!matrix.coverity'
run: ci/build.sh
- name: Upload coverage
if: matrix.coverage
run: ci/codecov.sh "upload"
- name: Run coverity
if: matrix.coverity && github.event_name == 'push' && (github.ref_name == 'develop' || github.ref_name == 'master')
run: ci/github/coverity.sh
env:
COVERITY_SCAN_NOTIFICATION_EMAIL: ${{ secrets.COVERITY_SCAN_NOTIFICATION_EMAIL }}
COVERITY_SCAN_TOKEN: ${{ secrets.COVERITY_SCAN_TOKEN }}
windows:
defaults:
run:
shell: cmd
strategy:
fail-fast: false
matrix:
include:
- { toolset: msvc-14.0, cxxstd: '14,latest', addrmd: '32,64', os: windows-2019 }
- { toolset: msvc-14.2, cxxstd: '14,17,20,latest', addrmd: '32,64', os: windows-2019 }
- { toolset: msvc-14.3, cxxstd: '14,17,20,latest', addrmd: '32,64', os: windows-2022 }
- { toolset: clang-win, cxxstd: '14,17,latest', addrmd: '32,64', os: windows-2022 }
- { toolset: gcc, cxxstd: '03,11,14,17,2a', addrmd: '64', os: windows-2019 }
runs-on: ${{matrix.os}}
steps:
- uses: actions/checkout@v3
- name: Fetch Boost.CI
uses: actions/checkout@v3
with:
repository: boostorg/boost-ci
ref: master
path: boost-ci-cloned
- name: Get CI scripts folder
run: |
REM Copy ci folder if not testing Boost.CI
if "%GITHUB_REPOSITORY%" == "%GITHUB_REPOSITORY:boost-ci=%" xcopy /s /e /q /i /y boost-ci-cloned\ci .\ci
rmdir /s /q boost-ci-cloned
- name: Setup Boost
run: ci\github\install.bat
- name: Run tests
if: '!matrix.coverage'
run: ci\build.bat
env:
B2_TOOLSET: ${{matrix.toolset}}
B2_CXXSTD: ${{matrix.cxxstd}}
B2_ADDRESS_MODEL: ${{matrix.addrmd}}
- name: Collect coverage
shell: powershell
if: matrix.coverage
run: ci\opencppcoverage.ps1
env:
B2_TOOLSET: ${{matrix.toolset}}
B2_CXXSTD: ${{matrix.cxxstd}}
B2_ADDRESS_MODEL: ${{matrix.addrmd}}
- name: Upload coverage
if: matrix.coverage
uses: codecov/codecov-action@v2
with:
files: __out/cobertura.xml
MSYS2:
defaults:
run:
shell: msys2 {0}
strategy:
fail-fast: false
matrix:
include:
- { sys: MINGW32, compiler: gcc, cxxstd: '03,11,17,20' }
- { sys: MINGW64, compiler: gcc, cxxstd: '03,11,17,20' }
runs-on: windows-latest
steps:
- uses: actions/checkout@v3
- name: Setup MSYS2 environment
uses: msys2/setup-msys2@v2
with:
msystem: ${{matrix.sys}}
update: true
install: git python
pacboy: gcc:p cmake:p ninja:p
- name: Fetch Boost.CI
uses: actions/checkout@v3
with:
repository: boostorg/boost-ci
ref: master
path: boost-ci-cloned
- name: Get CI scripts folder
run: |
# Copy ci folder if not testing Boost.CI
[[ "$GITHUB_REPOSITORY" =~ "boost-ci" ]] || cp -r boost-ci-cloned/ci .
rm -rf boost-ci-cloned
- name: Setup Boost
env:
B2_COMPILER: ${{matrix.compiler}}
B2_CXXSTD: ${{matrix.cxxstd}}
B2_SANITIZE: ${{matrix.sanitize}}
B2_STDLIB: ${{matrix.stdlib}}
run: ci/github/install.sh
- name: Run tests
run: ci/build.sh
# Run also the CMake tests to avoid having to setup another matrix for CMake on MSYS
- name: Run CMake tests
run: |
cd "$BOOST_ROOT"
mkdir __build_cmake_test__ && cd __build_cmake_test__
cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug -DBOOST_INCLUDE_LIBRARIES=$SELF -DBUILD_SHARED_LIBS=ON -DBUILD_TESTING=ON -DBoost_VERBOSE=ON ..
cmake --build . --target tests --config Debug -j$B2_JOBS
ctest --output-on-failure --build-config Debug
CMake:
defaults:
run:
shell: bash
strategy:
fail-fast: false
matrix:
include:
- { os: ubuntu-20.04, build_shared: ON, build_type: Debug, generator: 'Unix Makefiles' }
- { os: windows-2019, build_shared: ON, build_type: Debug, generator: 'Visual Studio 16 2019' }
timeout-minutes: 120
runs-on: ${{matrix.os}}
steps:
- uses: actions/checkout@v3
- name: Fetch Boost.CI
uses: actions/checkout@v3
with:
repository: boostorg/boost-ci
ref: master
path: boost-ci-cloned
- name: Get CI scripts folder
run: |
# Copy ci folder if not testing Boost.CI
[[ "$GITHUB_REPOSITORY" =~ "boost-ci" ]] || cp -r boost-ci-cloned/ci .
rm -rf boost-ci-cloned
- name: Setup Boost
env: {B2_DONT_BOOTSTRAP: 1}
run: source ci/github/install.sh
- name: Run CMake tests
run: |
cd "$BOOST_ROOT"
mkdir __build_cmake_test__ && cd __build_cmake_test__
cmake -G "${{matrix.generator}}" -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBOOST_INCLUDE_LIBRARIES=$SELF -DBUILD_SHARED_LIBS=${{matrix.build_shared}} -DBUILD_TESTING=ON -DBoost_VERBOSE=ON ..
cmake --build . --target tests --config ${{matrix.build_type}} -j$B2_JOBS
ctest --output-on-failure --build-config ${{matrix.build_type}}
- name: Run CMake subdir tests
run: |
cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_test" # New unified folder
[ -d "$cmake_test_folder" ] || cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_subdir_test"
cd "$cmake_test_folder"
mkdir __build_cmake_subdir_test__ && cd __build_cmake_subdir_test__
cmake -G "${{matrix.generator}}" -DBOOST_CI_INSTALL_TEST=OFF -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBUILD_SHARED_LIBS=${{matrix.build_shared}} ..
cmake --build . --config ${{matrix.build_type}} -j$B2_JOBS
ctest --output-on-failure --build-config ${{matrix.build_type}}
- name: Install Library
run: |
cd "$BOOST_ROOT"
mkdir __build_cmake_install_test__ && cd __build_cmake_install_test__
cmake -G "${{matrix.generator}}" -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBOOST_INCLUDE_LIBRARIES=$SELF -DBUILD_SHARED_LIBS=${{matrix.build_shared}} -DCMAKE_INSTALL_PREFIX=~/.local -DBoost_VERBOSE=ON -DBoost_DEBUG=ON ..
cmake --build . --target install --config ${{matrix.build_type}} -j$B2_JOBS
- name: Run CMake install tests
run: |
cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_test" # New unified folder
[ -d "$cmake_test_folder" ] || cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_install_test"
cd "$cmake_test_folder"
mkdir __build_cmake_install_test__ && cd __build_cmake_install_test__
cmake -G "${{matrix.generator}}" -DBOOST_CI_INSTALL_TEST=ON -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBUILD_SHARED_LIBS=${{matrix.build_shared}} -DCMAKE_PREFIX_PATH=~/.local ..
cmake --build . --config ${{matrix.build_type}} -j$B2_JOBS
ctest --output-on-failure --build-config ${{matrix.build_type}}
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/doc/html/
-87
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# Copyright (C) 2016 Daniel James.
# Distributed under the Boost Software License, Version 1.0. (See accompanying
# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
# Use Trusty to get a reasonably recent version of Boost.
sudo: required
dist: trusty
language: c++
addons:
apt:
packages:
- libxml2-utils
- g++-multilib
matrix:
include:
- compiler: gcc
env: |
label="gcc C++03/11";
user_config="using gcc : : g++-4.8 --coverage -fsanitize=address ;"
enable_coverage=1
CXXSTD=03,11
- compiler: gcc
env: |
label="gcc 32 bit C++11";
user_config="using gcc : : g++-4.8 -m32 -fsanitize=address ;"
CXXSTD=11
- compiler: clang
env: |
label="clang C++11/17";
user_config="using clang : : clang++ -fsanitize=address ;"
CXXSTD=11,17
# sanitized=address not available for 32-bit clang on travis.
- compiler: clang
env: |
label="clang 32 bit";
user_config="using clang : : clang++ -m32 ;"
CXXSTD=03
before_install:
- if [ -n $enable_coverage ]; then pip install --user cpp-coveralls; fi
before_script:
- export BOOST_VERSION=1.67.0
- export BOOST_FILENAME=boost_1_67_0
- export BOOST_ROOT=${HOME}/boost
- cd ${TRAVIS_BUILD_DIR}
- touch Jamroot.jam
- cd $HOME
- echo $user_config > ~/user-config.jam
- cat ~/user-config.jam
- |
# Pick snapshot to use
if [ "$TRAVIS_EVENT_TYPE" == "cron" ]
then
if [ "$TRAVIS_BRANCH" == "master" ]
then
snapshot=master
else
snapshot=develop
fi
else
#snapshot=stable
snapshot=master
fi
# Download and extract snapshot
echo "Downloading ${download_url}"
mkdir $HOME/download
cd $HOME/download
python ${TRAVIS_BUILD_DIR}/ci/download-boost-snapshot.py $snapshot
mv * ${BOOST_ROOT}
- rm -r ${BOOST_ROOT}/boost/unordered
- cd ${BOOST_ROOT}/tools/build
- mkdir ${HOME}/opt
- bash bootstrap.sh
- ./b2 install --prefix=$HOME/opt
after_success:
if [ -n $enable_coverage ]; then coveralls -r ${TRAVIS_BUILD_DIR} -b ${TRAVIS_BUILD_DIR}/test --gcov-options '\-lp' --include include/boost/unordered/ ; fi
script:
- cd ${TRAVIS_BUILD_DIR}/test
- ${HOME}/opt/bin/b2 -j 3 cxxstd=$CXXSTD -q include=${BOOST_ROOT} include=${TRAVIS_BUILD_DIR}/include
- xmllint --noout ${TRAVIS_BUILD_DIR}/doc/ref.xml
-34
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# Generated by `boostdep --cmake unordered`
# Copyright 2020, 2021 Peter Dimov
# Distributed under the Boost Software License, Version 1.0.
# https://www.boost.org/LICENSE_1_0.txt
cmake_minimum_required(VERSION 3.5...3.20)
project(boost_unordered VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
add_library(boost_unordered INTERFACE)
add_library(Boost::unordered ALIAS boost_unordered)
target_include_directories(boost_unordered INTERFACE include)
target_link_libraries(boost_unordered
INTERFACE
Boost::assert
Boost::config
Boost::container_hash
Boost::core
Boost::move
Boost::mp11
Boost::predef
Boost::preprocessor
Boost::throw_exception
Boost::tuple
Boost::type_traits
)
if(BUILD_TESTING AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/test/CMakeLists.txt")
add_subdirectory(test)
endif()
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Boost Software License - Version 1.0 - August 17th, 2003
Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
this license (the "Software") to use, reproduce, display, distribute,
execute, and transmit the Software, and to prepare derivative works of the
Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:
The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
a source language processor.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
-49
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# Boost.Unordered
Part of collection of the [Boost C++ Libraries](http://github.com/boostorg).
For accessing data based on key lookup, the C++ standard library offers `std::set`, `std::map`, `std::multiset` and `std::multimap`.
These are generally implemented using balanced binary trees so that lookup time has logarithmic complexity.
That is generally okay, but in many cases a hash table can perform better, as accessing data has constant complexity, on average.
The worst case complexity is linear, but that occurs rarely and with some care, can be avoided.
Also, the existing containers require a 'less than' comparison object to order their elements.
For some data types this is impossible to implement or isnt practical.
In contrast, a hash table only needs an equality function and a hash function for the key.
With this in mind, unordered associative containers were added to the C++ standard.
This is an implementation of the containers described in C++11, with some deviations from the standard in order to work with non-C++11 compilers and libraries.
### License
Distributed under the [Boost Software License, Version 1.0](http://www.boost.org/LICENSE_1_0.txt).
### Properties
* C++03
* Header-Only
### Build Status
Branch | GH Actions | Appveyor | codecov.io | Deps | Docs | Tests |
:-------------: | ---------- | -------- | ---------- | ---- | ---- | ----- |
[`master`](https://github.com/boostorg/unordered/tree/master) | [![CI](https://github.com/boostorg/unordered/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/boostorg/unordered/actions/workflows/ci.yml) | [![Build status](https://ci.appveyor.com/api/projects/status/github/boostorg/unordered?branch=master&svg=true)](https://ci.appveyor.com/project/danieljames/unordered-qtwe6/branch/master) | [![codecov](https://codecov.io/gh/boostorg/unordered/branch/master/graph/badge.svg)](https://codecov.io/gh/boostorg/unordered/branch/master) | [![Deps](https://img.shields.io/badge/deps-master-brightgreen.svg)](https://pdimov.github.io/boostdep-report/master/unordered.html) | [![Documentation](https://img.shields.io/badge/docs-master-brightgreen.svg)](https://www.boost.org/doc/libs/master/libs/unordered/doc/html/unordered.html) | [![Enter the Matrix](https://img.shields.io/badge/matrix-master-brightgreen.svg)](http://www.boost.org/development/tests/master/developer/unordered.html)
[`develop`](https://github.com/boostorg/unordered/tree/develop) | [![CI](https://github.com/boostorg/unordered/actions/workflows/ci.yml/badge.svg?branch=develop)](https://github.com/boostorg/unordered/actions/workflows/ci.yml) | [![Build status](https://ci.appveyor.com/api/projects/status/github/boostorg/unordered?branch=develop&svg=true)](https://ci.appveyor.com/project/danieljames/unordered-qtwe6/branch/develop) | [![codecov](https://codecov.io/gh/boostorg/unordered/branch/develop/graph/badge.svg)](https://codecov.io/gh/boostorg/unordered/branch/develop) | [![Deps](https://img.shields.io/badge/deps-develop-brightgreen.svg)](https://pdimov.github.io/boostdep-report/develop/unordered.html) | [![Documentation](https://img.shields.io/badge/docs-develop-brightgreen.svg)](https://www.boost.org/doc/libs/develop/libs/unordered/doc/html/unordered.html) | [![Enter the Matrix](https://img.shields.io/badge/matrix-develop-brightgreen.svg)](http://www.boost.org/development/tests/develop/developer/unordered.html)
### Directories
| Name | Purpose |
| ----------- | ------------------------------ |
| `doc` | documentation |
| `example` | examples |
| `include` | headers |
| `test` | unit tests |
### More information
* [Ask questions](http://stackoverflow.com/questions/ask?tags=c%2B%2B,boost,boost-unordered)
* [Report bugs](https://github.com/boostorg/unordered/issues): Be sure to mention Boost version, platform and compiler you're using. A small compilable code sample to reproduce the problem is always good as well.
* Submit your patches as pull requests against **develop** branch. Note that by submitting patches you agree to license your modifications under the [Boost Software License, Version 1.0](http://www.boost.org/LICENSE_1_0.txt).
* Discussions about the library are held on the [Boost developers mailing list](http://www.boost.org/community/groups.html#main). Be sure to read the [discussion policy](http://www.boost.org/community/policy.html) before posting and add the `[unordered]` tag at the beginning of the subject line.
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# Copyright 2017 Daniel James.
# Distributed under the Boost Software License, Version 1.0. (See accompanying
# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
# Using clang format 4.0
# http://llvm.org/releases/4.0.0/tools/clang/docs/ClangFormatStyleOptions.html
# Becuase you have to start somewhere.
BasedOnStyle: LLVM
# Basic settings
ColumnLimit: 80
NamespaceIndentation: All
ContinuationIndentWidth: 2
IndentWidth: 2
UseTab: Never
Language: Cpp
Standard: Cpp03
# Code layout
AlignAfterOpenBracket: DontAlign
AlignTrailingComments: true
BreakBeforeBraces: Custom
BraceWrapping:
AfterNamespace: false
AfterClass: true
AfterStruct: true
AfterUnion: true
AfterEnum: true
AfterFunction: true
AfterControlStatement: false
BeforeCatch: false
BeforeElse: false
PointerAlignment: Left
# Boost specific stuff
ForEachMacros: [ BOOST_FOREACH, UNORDERED_AUTO_TEST ]
-488
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@@ -1,488 +0,0 @@
// Copyright 2021 Peter Dimov.
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
#include <boost/unordered_map.hpp>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/core/detail/splitmix64.hpp>
#include <boost/config.hpp>
#ifdef HAVE_ABSEIL
# include "absl/container/node_hash_map.h"
# include "absl/container/flat_hash_map.h"
#endif
#ifdef HAVE_TSL_HOPSCOTCH
# include "tsl/hopscotch_map.h"
#endif
#ifdef HAVE_TSL_ROBIN
# include "tsl/robin_map.h"
#endif
#include <unordered_map>
#include <vector>
#include <memory>
#include <cstdint>
#include <iostream>
#include <iomanip>
#include <chrono>
using namespace std::chrono_literals;
static void print_time( std::chrono::steady_clock::time_point & t1, char const* label, std::uint32_t s, std::size_t size )
{
auto t2 = std::chrono::steady_clock::now();
std::cout << label << ": " << ( t2 - t1 ) / 1ms << " ms (s=" << s << ", size=" << size << ")\n";
t1 = t2;
}
constexpr unsigned N = 2'000'000;
constexpr int K = 10;
static std::vector<std::string> indices1, indices2;
static std::string make_index( unsigned x )
{
char buffer[ 64 ];
std::snprintf( buffer, sizeof(buffer), "pfx_%u_sfx", x );
return buffer;
}
static std::string make_random_index( unsigned x )
{
char buffer[ 64 ];
std::snprintf( buffer, sizeof(buffer), "pfx_%0*d_%u_sfx", x % 8 + 1, 0, x );
return buffer;
}
static void init_indices()
{
indices1.reserve( N*2+1 );
indices1.push_back( make_index( 0 ) );
for( unsigned i = 1; i <= N*2; ++i )
{
indices1.push_back( make_index( i ) );
}
indices2.reserve( N*2+1 );
indices2.push_back( make_index( 0 ) );
{
boost::detail::splitmix64 rng;
for( unsigned i = 1; i <= N*2; ++i )
{
indices2.push_back( make_random_index( static_cast<std::uint32_t>( rng() ) ) );
}
}
}
template<class Map> BOOST_NOINLINE void test_insert( Map& map, std::chrono::steady_clock::time_point & t1 )
{
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices1[ i ], i } );
}
print_time( t1, "Consecutive insert", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices2[ i ], i } );
}
print_time( t1, "Random insert", 0, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_lookup( Map& map, std::chrono::steady_clock::time_point & t1 )
{
std::uint32_t s;
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices1[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Consecutive lookup", s, map.size() );
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices2[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Random lookup", s, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::steady_clock::time_point & t1 )
{
auto it = map.begin();
while( it != map.end() )
{
if( it->second & 1 )
{
if constexpr( std::is_void_v< decltype( map.erase( it ) ) > )
{
map.erase( it++ );
}
else
{
it = map.erase( it );
}
}
else
{
++it;
}
}
print_time( t1, "Iterate and erase odd elements", 0, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::steady_clock::time_point & t1 )
{
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices1[ i ] );
}
print_time( t1, "Consecutive erase", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices2[ i ] );
}
print_time( t1, "Random erase", 0, map.size() );
std::cout << std::endl;
}
// counting allocator
static std::size_t s_alloc_bytes = 0;
static std::size_t s_alloc_count = 0;
template<class T> struct allocator
{
using value_type = T;
allocator() = default;
template<class U> allocator( allocator<U> const & ) noexcept
{
}
template<class U> bool operator==( allocator<U> const & ) const noexcept
{
return true;
}
template<class U> bool operator!=( allocator<U> const& ) const noexcept
{
return false;
}
T* allocate( std::size_t n ) const
{
s_alloc_bytes += n * sizeof(T);
s_alloc_count++;
return std::allocator<T>().allocate( n );
}
void deallocate( T* p, std::size_t n ) const noexcept
{
s_alloc_bytes -= n * sizeof(T);
s_alloc_count--;
std::allocator<T>().deallocate( p, n );
}
};
//
struct record
{
std::string label_;
long long time_;
std::size_t bytes_;
std::size_t count_;
};
static std::vector<record> times;
template<template<class...> class Map> BOOST_NOINLINE void test( char const* label )
{
std::cout << label << ":\n\n";
s_alloc_bytes = 0;
s_alloc_count = 0;
Map<std::string, std::uint32_t> map;
auto t0 = std::chrono::steady_clock::now();
auto t1 = t0;
test_insert( map, t1 );
std::cout << "Memory: " << s_alloc_bytes << " bytes in " << s_alloc_count << " allocations\n\n";
record rec = { label, 0, s_alloc_bytes, s_alloc_count };
test_lookup( map, t1 );
test_iteration( map, t1 );
test_lookup( map, t1 );
test_erase( map, t1 );
auto tN = std::chrono::steady_clock::now();
std::cout << "Total: " << ( tN - t0 ) / 1ms << " ms\n\n";
rec.time_ = ( tN - t0 ) / 1ms;
times.push_back( rec );
}
// multi_index emulation of unordered_map
template<class K, class V> struct pair
{
K first;
mutable V second;
};
using namespace boost::multi_index;
template<class K, class V> using multi_index_map = multi_index_container<
pair<K, V>,
indexed_by<
hashed_unique< member<pair<K, V>, K, &pair<K, V>::first> >
>,
::allocator< pair<K, V> >
>;
// aliases using the counting allocator
template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
template<class K, class V> using std_unordered_map =
std::unordered_map<K, V, std::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
template<class K, class V> using boost_unordered_map =
boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
#ifdef HAVE_ABSEIL
template<class K, class V> using absl_node_hash_map =
absl::node_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
template<class K, class V> using absl_flat_hash_map =
absl::flat_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
#endif
#ifdef HAVE_TSL_HOPSCOTCH
template<class K, class V> using tsl_hopscotch_map =
tsl::hopscotch_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_hopscotch_pg_map =
tsl::hopscotch_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
#ifdef HAVE_TSL_ROBIN
template<class K, class V> using tsl_robin_map =
tsl::robin_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_robin_pg_map =
tsl::robin_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
// fnv1a_hash
template<int Bits> struct fnv1a_hash_impl;
template<> struct fnv1a_hash_impl<32>
{
std::size_t operator()( std::string const& s ) const
{
std::size_t h = 0x811C9DC5u;
char const * first = s.data();
char const * last = first + s.size();
for( ; first != last; ++first )
{
h ^= static_cast<unsigned char>( *first );
h *= 0x01000193ul;
}
return h;
}
};
template<> struct fnv1a_hash_impl<64>
{
std::size_t operator()( std::string const& s ) const
{
std::size_t h = 0xCBF29CE484222325ull;
char const * first = s.data();
char const * last = first + s.size();
for( ; first != last; ++first )
{
h ^= static_cast<unsigned char>( *first );
h *= 0x00000100000001B3ull;
}
return h;
}
};
struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits > {};
template<class K, class V> using std_unordered_map_fnv1a =
std::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
template<class K, class V> using boost_unordered_map_fnv1a =
boost::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
template<class K, class V> using multi_index_map_fnv1a = multi_index_container<
pair<K, V>,
indexed_by<
hashed_unique< member<pair<K, V>, K, &pair<K, V>::first>, fnv1a_hash >
>,
::allocator< pair<K, V> >
>;
#ifdef HAVE_ABSEIL
template<class K, class V> using absl_node_hash_map_fnv1a =
absl::node_hash_map<K, V, fnv1a_hash, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
template<class K, class V> using absl_flat_hash_map_fnv1a =
absl::flat_hash_map<K, V, fnv1a_hash, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
#endif
#ifdef HAVE_TSL_HOPSCOTCH
template<class K, class V> using tsl_hopscotch_map_fnv1a =
tsl::hopscotch_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_hopscotch_pg_map_fnv1a =
tsl::hopscotch_pg_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
#ifdef HAVE_TSL_ROBIN
template<class K, class V> using tsl_robin_map_fnv1a =
tsl::robin_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_robin_pg_map_fnv1a =
tsl::robin_pg_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
//
int main()
{
init_indices();
#if 0
test<std_unordered_map>( "std::unordered_map" );
test<boost_unordered_map>( "boost::unordered_map" );
test<multi_index_map>( "multi_index_map" );
#ifdef HAVE_ABSEIL
test<absl_node_hash_map>( "absl::node_hash_map" );
test<absl_flat_hash_map>( "absl::flat_hash_map" );
#endif
#ifdef HAVE_TSL_HOPSCOTCH
test<tsl_hopscotch_map>( "tsl::hopscotch_map" );
test<tsl_hopscotch_pg_map>( "tsl::hopscotch_pg_map" );
#endif
#ifdef HAVE_TSL_ROBIN
test<tsl_robin_map>( "tsl::robin_map" );
test<tsl_robin_pg_map>( "tsl::robin_pg_map" );
#endif
#endif
test<std_unordered_map_fnv1a>( "std::unordered_map, FNV-1a" );
test<boost_unordered_map_fnv1a>( "boost::unordered_map, FNV-1a" );
test<multi_index_map_fnv1a>( "multi_index_map, FNV-1a" );
#ifdef HAVE_ABSEIL
test<absl_node_hash_map_fnv1a>( "absl::node_hash_map, FNV-1a" );
test<absl_flat_hash_map_fnv1a>( "absl::flat_hash_map, FNV-1a" );
#endif
#ifdef HAVE_TSL_HOPSCOTCH
test<tsl_hopscotch_map_fnv1a>( "tsl::hopscotch_map, FNV-1a" );
test<tsl_hopscotch_pg_map_fnv1a>( "tsl::hopscotch_pg_map, FNV-1a" );
#endif
#ifdef HAVE_TSL_ROBIN
test<tsl_robin_map_fnv1a>( "tsl::robin_map, FNV-1a" );
test<tsl_robin_pg_map_fnv1a>( "tsl::robin_pg_map, FNV-1a" );
#endif
std::cout << "---\n\n";
for( auto const& x: times )
{
std::cout << std::setw( 31 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
}
}
#ifdef HAVE_ABSEIL
# include "absl/container/internal/raw_hash_set.cc"
# include "absl/hash/internal/hash.cc"
# include "absl/hash/internal/low_level_hash.cc"
# include "absl/hash/internal/city.cc"
#endif
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// Copyright 2021 Peter Dimov.
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
#include <boost/unordered_map.hpp>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/core/detail/splitmix64.hpp>
#include <boost/config.hpp>
#ifdef HAVE_ABSEIL
# include "absl/container/node_hash_map.h"
# include "absl/container/flat_hash_map.h"
#endif
#ifdef HAVE_TSL_HOPSCOTCH
# include "tsl/hopscotch_map.h"
#endif
#ifdef HAVE_TSL_ROBIN
# include "tsl/robin_map.h"
#endif
#include <unordered_map>
#include <string_view>
#include <vector>
#include <memory>
#include <cstdint>
#include <iostream>
#include <iomanip>
#include <chrono>
using namespace std::chrono_literals;
static void print_time( std::chrono::steady_clock::time_point & t1, char const* label, std::uint32_t s, std::size_t size )
{
auto t2 = std::chrono::steady_clock::now();
std::cout << label << ": " << ( t2 - t1 ) / 1ms << " ms (s=" << s << ", size=" << size << ")\n";
t1 = t2;
}
constexpr unsigned N = 2'000'000;
constexpr int K = 10;
static std::vector<std::string> indices1, indices2;
static std::string make_index( unsigned x )
{
char buffer[ 64 ];
std::snprintf( buffer, sizeof(buffer), "pfx_%u_sfx", x );
return buffer;
}
static std::string make_random_index( unsigned x )
{
char buffer[ 64 ];
std::snprintf( buffer, sizeof(buffer), "pfx_%0*d_%u_sfx", x % 8 + 1, 0, x );
return buffer;
}
static void init_indices()
{
indices1.reserve( N*2+1 );
indices1.push_back( make_index( 0 ) );
for( unsigned i = 1; i <= N*2; ++i )
{
indices1.push_back( make_index( i ) );
}
indices2.reserve( N*2+1 );
indices2.push_back( make_index( 0 ) );
{
boost::detail::splitmix64 rng;
for( unsigned i = 1; i <= N*2; ++i )
{
indices2.push_back( make_random_index( static_cast<std::uint32_t>( rng() ) ) );
}
}
}
template<class Map> BOOST_NOINLINE void test_insert( Map& map, std::chrono::steady_clock::time_point & t1 )
{
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices1[ i ], i } );
}
print_time( t1, "Consecutive insert", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices2[ i ], i } );
}
print_time( t1, "Random insert", 0, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_lookup( Map& map, std::chrono::steady_clock::time_point & t1 )
{
std::uint32_t s;
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices1[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Consecutive lookup", s, map.size() );
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices2[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Random lookup", s, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::steady_clock::time_point & t1 )
{
auto it = map.begin();
while( it != map.end() )
{
if( it->second & 1 )
{
if constexpr( std::is_void_v< decltype( map.erase( it ) ) > )
{
map.erase( it++ );
}
else
{
it = map.erase( it );
}
}
else
{
++it;
}
}
print_time( t1, "Iterate and erase odd elements", 0, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::steady_clock::time_point & t1 )
{
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices1[ i ] );
}
print_time( t1, "Consecutive erase", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices2[ i ] );
}
print_time( t1, "Random erase", 0, map.size() );
std::cout << std::endl;
}
// counting allocator
static std::size_t s_alloc_bytes = 0;
static std::size_t s_alloc_count = 0;
template<class T> struct allocator
{
using value_type = T;
allocator() = default;
template<class U> allocator( allocator<U> const & ) noexcept
{
}
template<class U> bool operator==( allocator<U> const & ) const noexcept
{
return true;
}
template<class U> bool operator!=( allocator<U> const& ) const noexcept
{
return false;
}
T* allocate( std::size_t n ) const
{
s_alloc_bytes += n * sizeof(T);
s_alloc_count++;
return std::allocator<T>().allocate( n );
}
void deallocate( T* p, std::size_t n ) const noexcept
{
s_alloc_bytes -= n * sizeof(T);
s_alloc_count--;
std::allocator<T>().deallocate( p, n );
}
};
//
struct record
{
std::string label_;
long long time_;
std::size_t bytes_;
std::size_t count_;
};
static std::vector<record> times;
template<template<class...> class Map> BOOST_NOINLINE void test( char const* label )
{
std::cout << label << ":\n\n";
s_alloc_bytes = 0;
s_alloc_count = 0;
Map<std::string_view, std::uint32_t> map;
auto t0 = std::chrono::steady_clock::now();
auto t1 = t0;
test_insert( map, t1 );
std::cout << "Memory: " << s_alloc_bytes << " bytes in " << s_alloc_count << " allocations\n\n";
record rec = { label, 0, s_alloc_bytes, s_alloc_count };
test_lookup( map, t1 );
test_iteration( map, t1 );
test_lookup( map, t1 );
test_erase( map, t1 );
auto tN = std::chrono::steady_clock::now();
std::cout << "Total: " << ( tN - t0 ) / 1ms << " ms\n\n";
rec.time_ = ( tN - t0 ) / 1ms;
times.push_back( rec );
}
// multi_index emulation of unordered_map
template<class K, class V> struct pair
{
K first;
mutable V second;
};
using namespace boost::multi_index;
template<class K, class V> using multi_index_map = multi_index_container<
pair<K, V>,
indexed_by<
hashed_unique< member<pair<K, V>, K, &pair<K, V>::first> >
>,
::allocator< pair<K, V> >
>;
// aliases using the counting allocator
template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
template<class K, class V> using std_unordered_map =
std::unordered_map<K, V, std::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
template<class K, class V> using boost_unordered_map =
boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
#ifdef HAVE_ABSEIL
template<class K, class V> using absl_node_hash_map =
absl::node_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
template<class K, class V> using absl_flat_hash_map =
absl::flat_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
#endif
#ifdef HAVE_TSL_HOPSCOTCH
template<class K, class V> using tsl_hopscotch_map =
tsl::hopscotch_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_hopscotch_pg_map =
tsl::hopscotch_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
#ifdef HAVE_TSL_ROBIN
template<class K, class V> using tsl_robin_map =
tsl::robin_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_robin_pg_map =
tsl::robin_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
// fnv1a_hash
template<int Bits> struct fnv1a_hash_impl;
template<> struct fnv1a_hash_impl<32>
{
std::size_t operator()( std::string_view const& s ) const
{
std::size_t h = 0x811C9DC5u;
char const * first = s.data();
char const * last = first + s.size();
for( ; first != last; ++first )
{
h ^= static_cast<unsigned char>( *first );
h *= 0x01000193ul;
}
return h;
}
};
template<> struct fnv1a_hash_impl<64>
{
std::size_t operator()( std::string_view const& s ) const
{
std::size_t h = 0xCBF29CE484222325ull;
char const * first = s.data();
char const * last = first + s.size();
for( ; first != last; ++first )
{
h ^= static_cast<unsigned char>( *first );
h *= 0x00000100000001B3ull;
}
return h;
}
};
struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits > {};
template<class K, class V> using std_unordered_map_fnv1a =
std::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
template<class K, class V> using boost_unordered_map_fnv1a =
boost::unordered_map<K, V, fnv1a_hash, std::equal_to<K>, allocator_for<K, V>>;
template<class K, class V> using multi_index_map_fnv1a = multi_index_container<
pair<K, V>,
indexed_by<
hashed_unique< member<pair<K, V>, K, &pair<K, V>::first>, fnv1a_hash >
>,
::allocator< pair<K, V> >
>;
#ifdef HAVE_ABSEIL
template<class K, class V> using absl_node_hash_map_fnv1a =
absl::node_hash_map<K, V, fnv1a_hash, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
template<class K, class V> using absl_flat_hash_map_fnv1a =
absl::flat_hash_map<K, V, fnv1a_hash, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
#endif
#ifdef HAVE_TSL_HOPSCOTCH
template<class K, class V> using tsl_hopscotch_map_fnv1a =
tsl::hopscotch_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_hopscotch_pg_map_fnv1a =
tsl::hopscotch_pg_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
#ifdef HAVE_TSL_ROBIN
template<class K, class V> using tsl_robin_map_fnv1a =
tsl::robin_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_robin_pg_map_fnv1a =
tsl::robin_pg_map<K, V, fnv1a_hash, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
//
int main()
{
init_indices();
#if 0
test<std_unordered_map>( "std::unordered_map" );
test<boost_unordered_map>( "boost::unordered_map" );
test<multi_index_map>( "multi_index_map" );
#ifdef HAVE_ABSEIL
test<absl_node_hash_map>( "absl::node_hash_map" );
test<absl_flat_hash_map>( "absl::flat_hash_map" );
#endif
#ifdef HAVE_TSL_HOPSCOTCH
test<tsl_hopscotch_map>( "tsl::hopscotch_map" );
test<tsl_hopscotch_pg_map>( "tsl::hopscotch_pg_map" );
#endif
#ifdef HAVE_TSL_ROBIN
test<tsl_robin_map>( "tsl::robin_map" );
test<tsl_robin_pg_map>( "tsl::robin_pg_map" );
#endif
#endif
test<std_unordered_map_fnv1a>( "std::unordered_map, FNV-1a" );
test<boost_unordered_map_fnv1a>( "boost::unordered_map, FNV-1a" );
test<multi_index_map_fnv1a>( "multi_index_map, FNV-1a" );
#ifdef HAVE_ABSEIL
test<absl_node_hash_map_fnv1a>( "absl::node_hash_map, FNV-1a" );
test<absl_flat_hash_map_fnv1a>( "absl::flat_hash_map, FNV-1a" );
#endif
#ifdef HAVE_TSL_HOPSCOTCH
test<tsl_hopscotch_map_fnv1a>( "tsl::hopscotch_map, FNV-1a" );
test<tsl_hopscotch_pg_map_fnv1a>( "tsl::hopscotch_pg_map, FNV-1a" );
#endif
#ifdef HAVE_TSL_ROBIN
test<tsl_robin_map_fnv1a>( "tsl::robin_map, FNV-1a" );
test<tsl_robin_pg_map_fnv1a>( "tsl::robin_pg_map, FNV-1a" );
#endif
std::cout << "---\n\n";
for( auto const& x: times )
{
std::cout << std::setw( 31 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
}
}
#ifdef HAVE_ABSEIL
# include "absl/container/internal/raw_hash_set.cc"
# include "absl/hash/internal/hash.cc"
# include "absl/hash/internal/low_level_hash.cc"
# include "absl/hash/internal/city.cc"
#endif
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// Copyright 2021 Peter Dimov.
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
#include <boost/unordered_map.hpp>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/endian/conversion.hpp>
#include <boost/core/detail/splitmix64.hpp>
#include <boost/config.hpp>
#ifdef HAVE_ABSEIL
# include "absl/container/node_hash_map.h"
# include "absl/container/flat_hash_map.h"
#endif
#ifdef HAVE_TSL_HOPSCOTCH
# include "tsl/hopscotch_map.h"
#endif
#ifdef HAVE_TSL_ROBIN
# include "tsl/robin_map.h"
#endif
#include <unordered_map>
#include <vector>
#include <memory>
#include <cstdint>
#include <iostream>
#include <iomanip>
#include <chrono>
using namespace std::chrono_literals;
static void print_time( std::chrono::steady_clock::time_point & t1, char const* label, std::uint32_t s, std::size_t size )
{
auto t2 = std::chrono::steady_clock::now();
std::cout << label << ": " << ( t2 - t1 ) / 1ms << " ms (s=" << s << ", size=" << size << ")\n";
t1 = t2;
}
constexpr unsigned N = 2'000'000;
constexpr int K = 10;
static std::vector< std::uint32_t > indices1, indices2, indices3;
static void init_indices()
{
indices1.push_back( 0 );
for( unsigned i = 1; i <= N*2; ++i )
{
indices1.push_back( i );
}
indices2.push_back( 0 );
{
boost::detail::splitmix64 rng;
for( unsigned i = 1; i <= N*2; ++i )
{
indices2.push_back( static_cast<std::uint32_t>( rng() ) );
}
}
indices3.push_back( 0 );
for( unsigned i = 1; i <= N*2; ++i )
{
indices3.push_back( boost::endian::endian_reverse( static_cast<std::uint32_t>( i ) ) );
}
}
template<class Map> BOOST_NOINLINE void test_insert( Map& map, std::chrono::steady_clock::time_point & t1 )
{
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices1[ i ], i } );
}
print_time( t1, "Consecutive insert", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices2[ i ], i } );
}
print_time( t1, "Random insert", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices3[ i ], i } );
}
print_time( t1, "Consecutive reversed insert", 0, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_lookup( Map& map, std::chrono::steady_clock::time_point & t1 )
{
std::uint32_t s;
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices1[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Consecutive lookup", s, map.size() );
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices2[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Random lookup", s, map.size() );
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices3[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Consecutive reversed lookup", s, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::steady_clock::time_point & t1 )
{
auto it = map.begin();
while( it != map.end() )
{
if( it->second & 1 )
{
if constexpr( std::is_void_v< decltype( map.erase( it ) ) > )
{
map.erase( it++ );
}
else
{
it = map.erase( it );
}
}
else
{
++it;
}
}
print_time( t1, "Iterate and erase odd elements", 0, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::steady_clock::time_point & t1 )
{
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices1[ i ] );
}
print_time( t1, "Consecutive erase", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices2[ i ] );
}
print_time( t1, "Random erase", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices3[ i ] );
}
print_time( t1, "Consecutive reversed erase", 0, map.size() );
std::cout << std::endl;
}
// counting allocator
static std::size_t s_alloc_bytes = 0;
static std::size_t s_alloc_count = 0;
template<class T> struct allocator
{
using value_type = T;
allocator() = default;
template<class U> allocator( allocator<U> const & ) noexcept
{
}
template<class U> bool operator==( allocator<U> const & ) const noexcept
{
return true;
}
template<class U> bool operator!=( allocator<U> const& ) const noexcept
{
return false;
}
T* allocate( std::size_t n ) const
{
s_alloc_bytes += n * sizeof(T);
s_alloc_count++;
return std::allocator<T>().allocate( n );
}
void deallocate( T* p, std::size_t n ) const noexcept
{
s_alloc_bytes -= n * sizeof(T);
s_alloc_count--;
std::allocator<T>().deallocate( p, n );
}
};
//
struct record
{
std::string label_;
long long time_;
std::size_t bytes_;
std::size_t count_;
};
static std::vector<record> times;
template<template<class...> class Map> BOOST_NOINLINE void test( char const* label )
{
std::cout << label << ":\n\n";
s_alloc_bytes = 0;
s_alloc_count = 0;
Map<std::uint32_t, std::uint32_t> map;
auto t0 = std::chrono::steady_clock::now();
auto t1 = t0;
test_insert( map, t1 );
std::cout << "Memory: " << s_alloc_bytes << " bytes in " << s_alloc_count << " allocations\n\n";
record rec = { label, 0, s_alloc_bytes, s_alloc_count };
test_lookup( map, t1 );
test_iteration( map, t1 );
test_lookup( map, t1 );
test_erase( map, t1 );
auto tN = std::chrono::steady_clock::now();
std::cout << "Total: " << ( tN - t0 ) / 1ms << " ms\n\n";
rec.time_ = ( tN - t0 ) / 1ms;
times.push_back( rec );
}
// multi_index emulation of unordered_map
template<class K, class V> struct pair
{
K first;
mutable V second;
};
using namespace boost::multi_index;
template<class K, class V> using multi_index_map = multi_index_container<
pair<K, V>,
indexed_by<
hashed_unique< member<pair<K, V>, K, &pair<K, V>::first> >
>,
::allocator< pair<K, V> >
>;
// aliases using the counting allocator
template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
template<class K, class V> using std_unordered_map =
std::unordered_map<K, V, std::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
template<class K, class V> using boost_unordered_map =
boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
#ifdef HAVE_ABSEIL
template<class K, class V> using absl_node_hash_map =
absl::node_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
template<class K, class V> using absl_flat_hash_map =
absl::flat_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
#endif
#ifdef HAVE_TSL_HOPSCOTCH
template<class K, class V> using tsl_hopscotch_map =
tsl::hopscotch_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_hopscotch_pg_map =
tsl::hopscotch_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
#ifdef HAVE_TSL_ROBIN
template<class K, class V> using tsl_robin_map =
tsl::robin_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_robin_pg_map =
tsl::robin_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
int main()
{
init_indices();
test<std_unordered_map>( "std::unordered_map" );
test<boost_unordered_map>( "boost::unordered_map" );
test<multi_index_map>( "multi_index_map" );
#ifdef HAVE_ABSEIL
test<absl_node_hash_map>( "absl::node_hash_map" );
test<absl_flat_hash_map>( "absl::flat_hash_map" );
#endif
#ifdef HAVE_TSL_HOPSCOTCH
test<tsl_hopscotch_map>( "tsl::hopscotch_map" );
test<tsl_hopscotch_pg_map>( "tsl::hopscotch_pg_map" );
#endif
#ifdef HAVE_TSL_ROBIN
test<tsl_robin_map>( "tsl::robin_map" );
test<tsl_robin_pg_map>( "tsl::robin_pg_map" );
#endif
std::cout << "---\n\n";
for( auto const& x: times )
{
std::cout << std::setw( 25 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
}
}
#ifdef HAVE_ABSEIL
# include "absl/container/internal/raw_hash_set.cc"
# include "absl/hash/internal/hash.cc"
# include "absl/hash/internal/low_level_hash.cc"
# include "absl/hash/internal/city.cc"
#endif
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// Copyright 2021 Peter Dimov.
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING
#include <boost/unordered_map.hpp>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/endian/conversion.hpp>
#include <boost/core/detail/splitmix64.hpp>
#include <boost/config.hpp>
#ifdef HAVE_ABSEIL
# include "absl/container/node_hash_map.h"
# include "absl/container/flat_hash_map.h"
#endif
#ifdef HAVE_TSL_HOPSCOTCH
# include "tsl/hopscotch_map.h"
#endif
#ifdef HAVE_TSL_ROBIN
# include "tsl/robin_map.h"
#endif
#include <unordered_map>
#include <vector>
#include <memory>
#include <cstdint>
#include <iostream>
#include <iomanip>
#include <chrono>
using namespace std::chrono_literals;
static void print_time( std::chrono::steady_clock::time_point & t1, char const* label, std::uint64_t s, std::size_t size )
{
auto t2 = std::chrono::steady_clock::now();
std::cout << label << ": " << ( t2 - t1 ) / 1ms << " ms (s=" << s << ", size=" << size << ")\n";
t1 = t2;
}
constexpr unsigned N = 2'000'000;
constexpr int K = 10;
static std::vector< std::uint64_t > indices1, indices2, indices3;
static void init_indices()
{
indices1.push_back( 0 );
for( unsigned i = 1; i <= N*2; ++i )
{
indices1.push_back( i );
}
indices2.push_back( 0 );
{
boost::detail::splitmix64 rng;
for( unsigned i = 1; i <= N*2; ++i )
{
indices2.push_back( rng() );
}
}
indices3.push_back( 0 );
for( unsigned i = 1; i <= N*2; ++i )
{
indices3.push_back( boost::endian::endian_reverse( static_cast<std::uint64_t>( i ) ) );
}
}
template<class Map> BOOST_NOINLINE void test_insert( Map& map, std::chrono::steady_clock::time_point & t1 )
{
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices1[ i ], i } );
}
print_time( t1, "Consecutive insert", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices2[ i ], i } );
}
print_time( t1, "Random insert", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.insert( { indices3[ i ], i } );
}
print_time( t1, "Consecutive reversed insert", 0, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_lookup( Map& map, std::chrono::steady_clock::time_point & t1 )
{
std::uint64_t s;
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices1[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Consecutive lookup", s, map.size() );
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices2[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Random lookup", s, map.size() );
s = 0;
for( int j = 0; j < K; ++j )
{
for( unsigned i = 1; i <= N * 2; ++i )
{
auto it = map.find( indices3[ i ] );
if( it != map.end() ) s += it->second;
}
}
print_time( t1, "Consecutive reversed lookup", s, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_iteration( Map& map, std::chrono::steady_clock::time_point & t1 )
{
auto it = map.begin();
while( it != map.end() )
{
if( it->second & 1 )
{
if constexpr( std::is_void_v< decltype( map.erase( it ) ) > )
{
map.erase( it++ );
}
else
{
it = map.erase( it );
}
}
else
{
++it;
}
}
print_time( t1, "Iterate and erase odd elements", 0, map.size() );
std::cout << std::endl;
}
template<class Map> BOOST_NOINLINE void test_erase( Map& map, std::chrono::steady_clock::time_point & t1 )
{
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices1[ i ] );
}
print_time( t1, "Consecutive erase", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices2[ i ] );
}
print_time( t1, "Random erase", 0, map.size() );
for( unsigned i = 1; i <= N; ++i )
{
map.erase( indices3[ i ] );
}
print_time( t1, "Consecutive reversed erase", 0, map.size() );
std::cout << std::endl;
}
// counting allocator
static std::size_t s_alloc_bytes = 0;
static std::size_t s_alloc_count = 0;
template<class T> struct allocator
{
using value_type = T;
allocator() = default;
template<class U> allocator( allocator<U> const & ) noexcept
{
}
template<class U> bool operator==( allocator<U> const & ) const noexcept
{
return true;
}
template<class U> bool operator!=( allocator<U> const& ) const noexcept
{
return false;
}
T* allocate( std::size_t n ) const
{
s_alloc_bytes += n * sizeof(T);
s_alloc_count++;
return std::allocator<T>().allocate( n );
}
void deallocate( T* p, std::size_t n ) const noexcept
{
s_alloc_bytes -= n * sizeof(T);
s_alloc_count--;
std::allocator<T>().deallocate( p, n );
}
};
//
struct record
{
std::string label_;
long long time_;
std::size_t bytes_;
std::size_t count_;
};
static std::vector<record> times;
template<template<class...> class Map> BOOST_NOINLINE void test( char const* label )
{
std::cout << label << ":\n\n";
s_alloc_bytes = 0;
s_alloc_count = 0;
Map<std::uint64_t, std::uint64_t> map;
auto t0 = std::chrono::steady_clock::now();
auto t1 = t0;
test_insert( map, t1 );
std::cout << "Memory: " << s_alloc_bytes << " bytes in " << s_alloc_count << " allocations\n\n";
record rec = { label, 0, s_alloc_bytes, s_alloc_count };
test_lookup( map, t1 );
test_iteration( map, t1 );
test_lookup( map, t1 );
test_erase( map, t1 );
auto tN = std::chrono::steady_clock::now();
std::cout << "Total: " << ( tN - t0 ) / 1ms << " ms\n\n";
rec.time_ = ( tN - t0 ) / 1ms;
times.push_back( rec );
}
// multi_index emulation of unordered_map
template<class K, class V> struct pair
{
K first;
mutable V second;
};
using namespace boost::multi_index;
template<class K, class V> using multi_index_map = multi_index_container<
pair<K, V>,
indexed_by<
hashed_unique< member<pair<K, V>, K, &pair<K, V>::first> >
>,
::allocator< pair<K, V> >
>;
// aliases using the counting allocator
template<class K, class V> using allocator_for = ::allocator< std::pair<K const, V> >;
template<class K, class V> using std_unordered_map =
std::unordered_map<K, V, std::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
template<class K, class V> using boost_unordered_map =
boost::unordered_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>>;
#ifdef HAVE_ABSEIL
template<class K, class V> using absl_node_hash_map =
absl::node_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
template<class K, class V> using absl_flat_hash_map =
absl::flat_hash_map<K, V, absl::container_internal::hash_default_hash<K>, absl::container_internal::hash_default_eq<K>, allocator_for<K, V>>;
#endif
#ifdef HAVE_TSL_HOPSCOTCH
template<class K, class V> using tsl_hopscotch_map =
tsl::hopscotch_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_hopscotch_pg_map =
tsl::hopscotch_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
#ifdef HAVE_TSL_ROBIN
template<class K, class V> using tsl_robin_map =
tsl::robin_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
template<class K, class V> using tsl_robin_pg_map =
tsl::robin_pg_map<K, V, std::hash<K>, std::equal_to<K>, ::allocator< std::pair<K, V> >>;
#endif
int main()
{
init_indices();
test<std_unordered_map>( "std::unordered_map" );
test<boost_unordered_map>( "boost::unordered_map" );
test<multi_index_map>( "multi_index_map" );
#ifdef HAVE_ABSEIL
test<absl_node_hash_map>( "absl::node_hash_map" );
test<absl_flat_hash_map>( "absl::flat_hash_map" );
#endif
#ifdef HAVE_TSL_HOPSCOTCH
test<tsl_hopscotch_map>( "tsl::hopscotch_map" );
test<tsl_hopscotch_pg_map>( "tsl::hopscotch_pg_map" );
#endif
#ifdef HAVE_TSL_ROBIN
test<tsl_robin_map>( "tsl::robin_map" );
test<tsl_robin_pg_map>( "tsl::robin_pg_map" );
#endif
std::cout << "---\n\n";
for( auto const& x: times )
{
std::cout << std::setw( 25 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
}
}
#ifdef HAVE_ABSEIL
# include "absl/container/internal/raw_hash_set.cc"
# include "absl/hash/internal/hash.cc"
# include "absl/hash/internal/low_level_hash.cc"
# include "absl/hash/internal/city.cc"
#endif
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# Copyright 2005 Daniel James.
# Distributed under the Boost Software License, Version 1.0. (See accompanying
# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
import asciidoctor ;
path-constant images_location : ../ ;
path-constant admonishment_location : ../../../../doc/src/images ;
html unordered.html : unordered.adoc ;
xml unordered : unordered.qbk ;
boostbook standalone : unordered :
<xsl:param>html.stylesheet=../../../../doc/html/boostbook.css
<xsl:param>boost.root=../../../..
<xsl:param>boost.libraries=../../../libraries.htm
<xsl:param>navig.graphics=1
install html_ : unordered.html : <location>html ;
<xsl:param>chunk.first.sections=1
<xsl:param>chunk.section.depth=2
<xsl:param>generate.section.toc.level=2
<xsl:param>toc.section.depth=1
<xsl:param>toc.max.depth=1
pdf unordered.pdf : unordered.adoc ;
explicit unordered.pdf ;
<xsl:param>boost.compact.typedef=0
<xsl:param>boost.compact.function=0
<xsl:param>boost.compact.enum=0
install pdf_ : unordered.pdf : <location>pdf ;
explicit pdf_ ;
# PDF Options:
# TOC Generation: this is needed for FOP-0.9 and later:
<xsl:param>fop1.extensions=0
<format>pdf:<xsl:param>xep.extensions=1
# TOC generation: this is needed for FOP 0.2, but must not be set to zero for FOP-0.9!
<format>pdf:<xsl:param>fop.extensions=0
# No indent on body text:
<format>pdf:<xsl:param>body.start.indent=0pt
# Margin size:
<format>pdf:<xsl:param>page.margin.inner=0.5in
# Margin size:
<format>pdf:<xsl:param>page.margin.outer=0.5in
# Paper type = A4
<format>pdf:<xsl:param>paper.type=A4
# Yes, we want graphics for admonishments:
<xsl:param>admon.graphics=1
# Set this one for PDF generation *only*:
# default png graphics are awful in PDF form,
# better use SVG's instead:
<format>pdf:<xsl:param>admon.graphics.extension=".svg"
<format>pdf:<xsl:param>use.role.for.mediaobject=1
<format>pdf:<xsl:param>preferred.mediaobject.role=print
<format>pdf:<xsl:param>img.src.path=$(images_location)/
#<format>pdf:<xsl:param>admon.graphics.path=$(admonishment_location)
<format>pdf:<xsl:param>draft.mode="no"
<format>pdf:<xsl:param>boost.url.prefix=http://www.boost.org/doc/libs/release/libs/unordered/doc/html
;
###############################################################################
alias boostdoc ;
explicit boostdoc ;
alias boostrelease : html_ ;
explicit boostrelease ;
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<!--
Copyright Daniel James 2008-2009
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
-->
<section id="unordered.bibliography">
<title>Bibliography</title>
<bibliography>
<biblioentry>
<biblioset relation="journal">
<title>C/C++ Users Journal</title>
<date>February, 2006</date>
</biblioset>
<biblioset relation="article">
<authorgroup>
<author>
<firstname>Pete</firstname>
<surname>Becker</surname>
</author>
</authorgroup>
<title><ulink url="http://www.ddj.com/cpp/184402066">STL and TR1: Part III - Unordered containers</ulink></title>
</biblioset>
<para>An introducation to the standard unordered containers.</para>
</biblioentry>
</bibliography>
</section>
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[/ Copyright 2006-2008 Daniel James.
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) ]
[section:buckets The Data Structure]
The containers are made up of a number of 'buckets', each of which can contain
any number of elements. For example, the following diagram shows an [classref
boost::unordered_set unordered_set] with 7 buckets containing 5 elements, `A`,
`B`, `C`, `D` and `E` (this is just for illustration, containers will typically
have more buckets).
[diagram buckets]
In order to decide which bucket to place an element in, the container applies
the hash function, `Hash`, to the element's key (for `unordered_set` and
`unordered_multiset` the key is the whole element, but is referred to as the key
so that the same terminology can be used for sets and maps). This returns a
value of type `std::size_t`. `std::size_t` has a much greater range of values
then the number of buckets, so that container applies another transformation to
that value to choose a bucket to place the element in.
Retrieving the elements for a given key is simple. The same process is applied
to the key to find the correct bucket. Then the key is compared with the
elements in the bucket to find any elements that match (using the equality
predicate `Pred`). If the hash function has worked well the elements will be
evenly distributed amongst the buckets so only a small number of elements will
need to be examined.
There is [link unordered.hash_equality more information on hash functions and
equality predicates in the next section].
You can see in the diagram that `A` & `D` have been placed in the same bucket.
When looking for elements in this bucket up to 2 comparisons are made, making
the search slower. This is known as a collision. To keep things fast we try to
keep collisions to a minimum.
'''
<table frame="all"><title>Methods for Accessing Buckets</title>
<tgroup cols="2">
<thead><row>
<entry><para>Method</para></entry>
<entry><para>Description</para></entry>
</row></thead>
<tbody>
<row>
<entry>'''`size_type bucket_count() const`'''</entry>
<entry>'''The number of buckets.'''</entry>
</row>
<row>
<entry>'''`size_type max_bucket_count() const`'''</entry>
<entry>'''An upper bound on the number of buckets.'''</entry>
</row>
<row>
<entry>'''`size_type bucket_size(size_type n) const`'''</entry>
<entry>'''The number of elements in bucket `n`.'''</entry>
</row>
<row>
<entry>'''`size_type bucket(key_type const& k) const`'''</entry>
<entry>'''Returns the index of the bucket which would contain k'''</entry>
</row>
<row>
<entry>'''`local_iterator begin(size_type n);`'''</entry>
<entry morerows='5'>'''Return begin and end iterators for bucket `n`.'''</entry>
</row>
<row>
<entry>'''`local_iterator end(size_type n);`'''</entry>
</row>
<row>
<entry>'''`const_local_iterator begin(size_type n) const;`'''</entry>
</row>
<row>
<entry>'''`const_local_iterator end(size_type n) const;`'''</entry>
</row>
<row>
<entry>'''`const_local_iterator cbegin(size_type n) const;`'''</entry>
</row>
<row>
<entry>'''`const_local_iterator cend(size_type n) const;`'''</entry>
</row>
</tbody>
</tgroup>
</table>
'''
[h2 Controlling the number of buckets]
As more elements are added to an unordered associative container, the number
of elements in the buckets will increase causing performance to degrade.
To combat this the containers increase the bucket count as elements are inserted.
You can also tell the container to change the bucket count (if required) by
calling `rehash`.
The standard leaves a lot of freedom to the implementer to decide how the
number of buckets are chosen, but it does make some requirements based on the
container's 'load factor', the average number of elements per bucket.
Containers also have a 'maximum load factor' which they should try to keep the
load factor below.
You can't control the bucket count directly but there are two ways to
influence it:
* Specify the minimum number of buckets when constructing a container or
when calling `rehash`.
* Suggest a maximum load factor by calling `max_load_factor`.
`max_load_factor` doesn't let you set the maximum load factor yourself, it just
lets you give a /hint/. And even then, the draft standard doesn't actually
require the container to pay much attention to this value. The only time the
load factor is /required/ to be less than the maximum is following a call to
`rehash`. But most implementations will try to keep the number of elements
below the max load factor, and set the maximum load factor to be the same as
or close to the hint - unless your hint is unreasonably small or large.
[table Methods for Controlling Bucket Size
[[Method] [Description]]
[
[`X(size_type n)`]
[Construct an empty container with at least `n` buckets (`X` is the container type).]
]
[
[`X(InputIterator i, InputIterator j, size_type n)`]
[Construct an empty container with at least `n` buckets and insert elements
from the range \[`i`, `j`) (`X` is the container type).]
]
[
[`float load_factor() const`]
[The average number of elements per bucket.]
]
[
[`float max_load_factor() const`]
[Returns the current maximum load factor.]
]
[
[`float max_load_factor(float z)`]
[Changes the container's maximum load factor, using `z` as a hint.]
]
[
[`void rehash(size_type n)`]
[Changes the number of buckets so that there at least n buckets, and
so that the load factor is less than the maximum load factor.]
]
]
[h2 Iterator Invalidation]
It is not specified how member functions other than `rehash` affect
the bucket count, although `insert` is only allowed to invalidate iterators
when the insertion causes the load factor to be greater than or equal to the
maximum load factor. For most implementations this means that insert will only
change the number of buckets when this happens. While iterators can be
invalidated by calls to `insert` and `rehash`, pointers and references to the
container's elements are never invalidated.
In a similar manner to using `reserve` for `vector`s, it can be a good idea
to call `rehash` before inserting a large number of elements. This will get
the expensive rehashing out of the way and let you store iterators, safe in
the knowledge that they won't be invalidated. If you are inserting `n`
elements into container `x`, you could first call:
x.rehash((x.size() + n) / x.max_load_factor() + 1);
[blurb Note: `rehash`'s argument is the minimum number of buckets, not the
number of elements, which is why the new size is divided by the maximum load factor. The
`+ 1` guarantees there is no invalidation; without it, reallocation could occur
if the number of bucket exactly divides the target size, since the container is
allowed to rehash when the load factor is equal to the maximum load factor.]
[endsect]
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[/ Copyright 2008 Daniel James.
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) ]
[section:changes Change Log]
[h2 Review Version]
Initial review version, for the review conducted from 7th December 2007 to
16th December 2007.
[h2 1.35.0 Add-on - 31st March 2008]
Unofficial release uploaded to vault, to be used with Boost 1.35.0. Incorporated
many of the suggestions from the review.
* Improved portability thanks to Boost regression testing.
* Fix lots of typos, and clearer text in the documentation.
* Fix floating point to `std::size_t` conversion when calculating sizes from
the max load factor, and use `double` in the calculation for greater accuracy.
* Fix some errors in the examples.
[h2 Boost 1.36.0]
First official release.
* Rearrange the internals.
* Move semantics - full support when rvalue references are available, emulated
using a cut down version of the Adobe move library when they are not.
* Emplace support when rvalue references and variadic template are available.
* More efficient node allocation when rvalue references and variadic template
are available.
* Added equality operators.
[h2 Boost 1.37.0]
* Rename overload of `emplace` with hint, to `emplace_hint` as specified in
[@http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2008/n2691.pdf n2691].
* Provide forwarding headers at `<boost/unordered/unordered_map_fwd.hpp>` and
`<boost/unordered/unordered_set_fwd.hpp>`.
* Move all the implementation inside `boost/unordered`, to assist
modularization and hopefully make it easier to track changes in subversion.
[h2 Boost 1.38.0]
* Use [@boost:/libs/utility/swap.html `boost::swap`].
* [@https://svn.boost.org/trac/boost/ticket/2237 Ticket 2237]:
Document that the equality and inequality operators are undefined for two
objects if their equality predicates aren't equivalent. Thanks to Daniel
Krügler.
* [@https://svn.boost.org/trac/boost/ticket/1710 Ticket 1710]:
Use a larger prime number list. Thanks to Thorsten Ottosen and Hervé
Brönnimann.
* Use
[@boost:/libs/type_traits/doc/html/boost_typetraits/category/alignment.html
aligned storage] to store the types. This changes the way the allocator is
used to construct nodes. It used to construct the node with two calls to
the allocator's `construct` method - once for the pointers and once for the
value. It now constructs the node with a single call to construct and
then constructs the value using in place construction.
* Add support for C++0x initializer lists where they're available (currently
only g++ 4.4 in C++0x mode).
[h2 Boost 1.39.0]
* [@https://svn.boost.org/trac/boost/ticket/2756 Ticket 2756]: Avoid a warning
on Visual C++ 2009.
* Some other minor internal changes to the implementation, tests and
documentation.
* Avoid an unnecessary copy in `operator[]`.
* [@https://svn.boost.org/trac/boost/ticket/2975 Ticket 2975]: Fix length of
prime number list.
[h2 Boost 1.40.0]
* [@https://svn.boost.org/trac/boost/ticket/2975 Ticket 2975]:
Store the prime list as a preprocessor sequence - so that it will always get
the length right if it changes again in the future.
* [@https://svn.boost.org/trac/boost/ticket/1978 Ticket 1978]:
Implement `emplace` for all compilers.
* [@https://svn.boost.org/trac/boost/ticket/2908 Ticket 2908],
[@https://svn.boost.org/trac/boost/ticket/3096 Ticket 3096]:
Some workarounds for old versions of borland, including adding explicit
destructors to all containers.
* [@https://svn.boost.org/trac/boost/ticket/3082 Ticket 3082]:
Disable incorrect Visual C++ warnings.
* Better configuration for C++0x features when the headers aren't available.
* Create less buckets by default.
[h2 Boost 1.41.0 - Major update]
* The original version made heavy use of macros to sidestep some of the older
compilers' poor template support. But since I no longer support those
compilers and the macro use was starting to become a maintenance burden it
has been rewritten to use templates instead of macros for the implementation
classes.
* The container objcet is now smaller thanks to using `boost::compressed_pair`
for EBO and a slightly different function buffer - now using a bool instead
of a member pointer.
* Buckets are allocated lazily which means that constructing an empty container
will not allocate any memory.
[endsect]
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[/ Copyright 2006-2008 Daniel James.
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) ]
[section:comparison Comparison with Associative Containers]
[table Interface differences.
[[Associative Containers] [Unordered Associative Containers]]
[
[Parameterized by an ordering relation `Compare`]
[Parameterized by a function object `Hash` and an equivalence relation
`Pred`]
]
[
[Keys can be compared using `key_compare` which is accessed by member function `key_comp()`,
values can be compared using `value_compare` which is accessed by member function `value_comp()`.]
[Keys can be hashed using `hasher` which is accessed by member function `hash_function()`,
and checked for equality using `key_equal` which is accessed by member function `key_eq()`.
There is no function object for compared or hashing values.]
]
[
[Constructors have optional extra parameters for the comparison object.]
[Constructors have optional extra parameters for the initial minimum
number of buckets, a hash function and an equality object.]
]
[
[Keys `k1`, `k2` are considered equivalent if
`!Compare(k1, k2) && !Compare(k2, k1)`]
[Keys `k1`, `k2` are considered equivalent if `Pred(k1, k2)`]
]
[
[Member function `lower_bound(k)` and `upper_bound(k)`]
[No equivalent. Since the elements aren't ordered `lower_bound` and
`upper_bound` would be meaningless.]
]
[
[`equal_range(k)` returns an empty range at the position that k
would be inserted if k isn't present in the container.]
[`equal_range(k)` returns a range at the end of the container if
k isn't present in the container. It can't return a positioned
range as k could be inserted into multiple place. To find out the
bucket that k would be inserted into use `bucket(k)`. But remember
that an insert can cause the container to rehash - meaning that the
element can be inserted into a different bucket.]
]
[
[`iterator`, `const_iterator` are of the bidirectional category.]
[`iterator`, `const_iterator` are of at least the forward category.]
]
[
[Iterators, pointers and references to the container's elements are
never invalidated.]
[[link unordered.buckets.iterator_invalidation Iterators can
be invalidated by calls to insert or rehash]. Pointers and
references to the container's elements are never invalidated.]
]
[
[Iterators iterate through the container in the order defined by
the comparison object.]
[Iterators iterate through the container in an arbitrary order, that
can change as elements are inserted. Although, equivalent elements
are always adjacent.]
]
[
[No equivalent]
[Local iterators can be used to iterate through individual buckets.
(I don't think that the order of local iterators and iterators are
required to have any correspondence.)]
]
[
[Can be compared using the `==`, `!=`, `<`, `<=`, `>`, `>=` operators.]
[No comparison operators are defined in the standard, although
[link unordered.rationale.equality_operators
implementations might extend the containers to support `==` and
`!=`].]
]
[
[]
[When inserting with a hint, implementations are permitted to ignore
the hint.]
]
[
[`erase` never throws an exception]
[The containers' hash or predicate function can throw exceptions
from `erase`]
]
]
[table Complexity Guarantees
[[Operation] [Associative Containers] [Unordered Associative Containers]]
[
[Construction of empty container]
[constant]
[O(/n/) where /n/ is the minimum number of buckets.]
]
[
[Construction of container from a range of /N/ elements]
[O(/N/ log /N/), O(/N/) if the range is sorted with `value_comp()`]
[Average case O(/N/), worst case
O(/N/'''<superscript>2</superscript>''')]
]
[
[Insert a single element]
[logarithmic]
[Average case constant, worst case linear]
]
[
[Insert a single element with a hint]
[Amortized constant if t elements inserted right after hint,
logarithmic otherwise]
[Average case constant, worst case linear (ie. the same as
a normal insert).]
]
[
[Inserting a range of /N/ elements]
[ /N/ log(`size()`+/N/) ]
[Average case O(/N/), worst case O(/N/ * `size()`)]
]
[
[Erase by key, `k`]
[O(log(`size()`) + `count(k)`)]
[Average case: O(`count(k)`), Worst case: O(`size()`)]
]
[
[Erase a single element by iterator]
[Amortized constant]
[Average case: O(1), Worst case: O(`size()`)]
]
[
[Erase a range of /N/ elements]
[O(log(`size()`) + /N/)]
[Average case: O(/N/), Worst case: O(`size()`)]
]
[
[Clearing the container]
[O(`size()`)]
[O(`size()`)]
]
[
[Find]
[logarithmic]
[Average case: O(1), Worst case: O(`size()`)]
]
[/ TODO: Average case is probably wrong. ]
[
[Count]
[O(log(`size()`) + `count(k)`)]
[Average case: O(1), Worst case: O(`size()`)]
]
[
[`equal_range(k)`]
[logarithmic]
[Average case: O(`count(k)`), Worst case: O(`size()`)]
]
[
[`lower_bound`,`upper_bound`]
[logarithmic]
[n/a]
]
]
[endsect]
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[/ Copyright 2006-2008 Daniel James.
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) ]
[section:hash_equality Equality Predicates and Hash Functions]
While the associative containers use an ordering relation to specify how the
elements are stored, the unordered associative containers use an equality
predicate and a hash function. For example, [classref boost::unordered_map]
is declared as:
template <
class Key, class Mapped,
class Hash = ``[classref boost::hash]``<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<std::pair<Key const, Mapped> > >
class ``[classref boost::unordered_map unordered_map]``;
The hash function comes first as you might want to change the hash function
but not the equality predicate. For example, if you wanted to use the
[@http://www.isthe.com/chongo/tech/comp/fnv/ FNV-1 hash] you could write:
[import src_code/dictionary.cpp]
[case_sensitive_dictionary_fnv]
There is an [@boost:/libs/unordered/examples/fnv1.hpp implementation
of FNV-1] in the examples directory.
If you wish to use a different equality function,
you will also need to use a matching hash function. For
example, to implement a case insensitive dictionary you need to define a
case insensitive equality predicate and hash function:
[case_insensitive_functions]
Which you can then use in a case insensitive dictionary:
[case_insensitive_dictionary]
This is a simplified version of the example at
[@boost:/libs/unordered/examples/case_insensitive.hpp /libs/unordered/examples/case_insensitive.hpp]
which supports other locales and string types.
[caution
Be careful when using the equality (`==`) operator with custom equality
predicates, especially if you're using a function pointer. If you compare two
containers with different equality predicates then the result is undefined.
For most stateless function objects this is impossible - since you can only
compare objects with the same equality predicate you know the equality
predicates must be equal. But if you're using function pointers or a stateful
equality predicate (e.g. boost::function) then you can get into trouble.
]
[h2 Custom Types]
Similarly, a custom hash function can be used for custom types:
[import src_code/point1.cpp]
[point_example1]
Since the default hash function is [link hash Boost.Hash],
we can [link hash.custom extend it to support the type]
so that the hash function doesn't need to be explicitly given:
[import src_code/point2.cpp]
[point_example2]
See the [link hash.custom Boost.Hash documentation] for more detail on how to
do this. Remember that it relies on extensions to the draft standard - so it
won't work on other implementations of the unordered associative containers.
[table Methods for accessing the hash and equality functions.
[[Method] [Description]]
[
[`hasher hash_function() const`]
[Returns the container's hash function.]
]
[
[`key_equal key_eq() const`]
[Returns the container's key equality function.]
]
]
[endsect]
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[/ Copyright 2006-2008 Daniel James.
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) ]
[def __tr1__
[@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1836.pdf
C++ Standard Library Technical Report]]
[def __boost-tr1__
[@http://www.boost.org/doc/html/boost_tr1.html
Boost.TR1]]
[def __draft__
[@http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2009/n2960.pdf
Working Draft of the C++ Standard]]
[def __hash-table__ [@http://en.wikipedia.org/wiki/Hash_table
hash table]]
[def __hash-function__ [@http://en.wikipedia.org/wiki/Hash_function
hash function]]
[section:intro Introduction]
For accessing data based on key lookup, the C++ standard library offers `std::set`,
`std::map`, `std::multiset` and `std::multimap`. These are generally
implemented using balanced binary trees so that lookup time has
logarithmic complexity. That is generally okay, but in many cases a
__hash-table__ can perform better, as accessing data has constant complexity,
on average. The worst case complexity is linear, but that occurs rarely and
with some care, can be avoided.
Also, the existing containers require a 'less than' comparison object
to order their elements. For some data types this is impossible to implement
or isn't practical. In contrast, a hash table only needs an equality function
and a hash function for the key.
With this in mind, the __tr1__ introduced the unordered associative containers,
which are implemented using hash tables, and they have now been added to the
__draft__.
This library supplies an almost complete implementation of the specification in
the __draft__.
`unordered_set` and `unordered_multiset` are defined in the header
<[headerref boost/unordered_set.hpp]>
namespace boost {
template <
class Key,
class Hash = ``[classref boost::hash]``<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<Key> >
class ``[classref boost::unordered_set unordered_set]``;
template<
class Key,
class Hash = ``[classref boost::hash]``<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<Key> >
class ``[classref boost::unordered_multiset unordered_multiset]``;
}
`unordered_map` and `unordered_multimap` are defined in the header
<[headerref boost/unordered_map.hpp]>
namespace boost {
template <
class Key, class Mapped,
class Hash = ``[classref boost::hash]``<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<Key> >
class ``[classref boost::unordered_map unordered_map]``;
template<
class Key, class Mapped,
class Hash = ``[classref boost::hash]``<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<Key> >
class ``[classref boost::unordered_multimap unordered_multimap]``;
}
When using Boost.TR1, these classes are included from `<unordered_set>` and
`<unordered_map>`, with the classes added to the `std::tr1` namespace.
The containers are used in a similar manner to the normal associative
containers:
[import src_code/intro.cpp]
[intro_example1_2]
But since the elements aren't ordered, the output of:
[intro_example1_3]
can be in any order. For example, it might be:
two,2
one,1
three,3
To store an object in an unordered associative container requires both an
key equality function and a hash function. The default function objects in
the standard containers support a few basic types including integer types,
floating point types, pointer types, and the standard strings. Since
Boost.Unordered uses [classref boost::hash] it also supports some other types,
including standard containers. To use any types not supported by these methods
you have to [link hash.custom extend Boost.Hash to support the type] or use
your own custom equality predicates and hash functions. See the
[link unordered.hash_equality Equality Predicates and Hash Functions] section
for more details.
There are other differences, which are listed in the
[link unordered.comparison Comparison with Associative Containers] section.
[endsect]
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# Building Boost from the Tip of Develop
To build Boost from the tip of the develop branch without cloning the entire
history, use the command below:
Linux:
```bash
cwd=$(pwd) \
&& cd ~ \
&& git clone -b develop --depth 1 --recurse-submodules --shallow-submodules --jobs 8 https://github.com/boostorg/boost.git boost-develop-beta \
&& cd boost-develop-beta \
&& ./bootstrap.sh \
&& ./b2 install --prefix=boost-install cxxstd=17 \
&& echo "Boost successfully installed into $(realpath boost-install)!
Add this to your CMake toolchain file.
list(APPEND CMAKE_PREFIX_PATH $(realpath boost-install))
" \
&& cd $cwd
```
Windows (using plain Command Prompt):
```bat
cmd /v
set cwd=%cd% ^
&& cd %homepath% ^
&& git clone -b develop --depth 1 --recurse-submodules --shallow-submodules --jobs 8 https://github.com/boostorg/boost.git boost-develop-beta ^
&& cd boost-develop-beta ^
&& bootstrap.bat ^
&& b2 install --prefix=boost-install cxxstd=17 address-model=64 ^
&& echo Boost successfully installed into !cd!\boost-install! ^
&& echo Add this to your CMake toolchain file. ^
&& echo list(APPEND CMAKE_PREFIX_PATH !cd:\=/!/boost-install) ^
&& cd !cwd! ^
&& exit
```
Note: you can build Boost with a specific compiler by setting the toolset in
the `./b2` command above. To build with clang, specify `toolset=clang`; to build
with a specific version of gcc, clang or msvc, specify e.g. `toolset=gcc-12` for GCC
12, `clang-14` for Clang 14, `msvc-14.3` for MSVC 14.3. The value of `cxxstd`
can also be set to other values such as 11 for C++11, 14 for C++14, etc.
For more info on what's possible, check out this link on b2:
https://www.boost.org/doc/libs/develop/tools/build/doc/html/index.html#bbv2.overview.builtins.features
This should hopefully cover the two most common cases of building a dependency,
setting the compiler and C++ standard used.
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[/ Copyright 2006-2008 Daniel James.
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) ]
[def __wang__
[@http://www.concentric.net/~Ttwang/tech/inthash.htm
Thomas Wang's article on integer hash functions]]
[section:rationale Implementation Rationale]
The intent of this library is to implement the unordered
containers in the draft standard, so the interface was fixed. But there are
still some implementation decisions to make. The priorities are
conformance to the standard and portability.
The [@http://en.wikipedia.org/wiki/Hash_table wikipedia article on hash tables]
has a good summary of the implementation issues for hash tables in general.
[h2 Data Structure]
By specifying an interface for accessing the buckets of the container the
standard pretty much requires that the hash table uses chained addressing.
It would be conceivable to write a hash table that uses another method. For
example, it could use open addressing, and use the lookup chain to act as a
bucket but there are a some serious problems with this:
* The draft standard requires that pointers to elements aren't invalidated, so
the elements can't be stored in one array, but will need a layer of
indirection instead - losing the efficiency and most of the memory gain,
the main advantages of open addressing.
* Local iterators would be very inefficient and may not be able to
meet the complexity requirements.
* There are also the restrictions on when iterators can be invalidated. Since
open addressing degrades badly when there are a high number of collisions the
restrictions could prevent a rehash when it's really needed. The maximum load
factor could be set to a fairly low value to work around this - but the
standard requires that it is initially set to 1.0.
* And since the standard is written with a eye towards chained
addressing, users will be surprised if the performance doesn't reflect that.
So chained addressing is used.
For containers with unique keys I store the buckets in a single-linked list.
There are other possible data structures (such as a double-linked list)
that allow for some operations to be faster (such as erasing and iteration)
but the possible gain seems small compared to the extra memory needed.
The most commonly used operations (insertion and lookup) would not be improved
at all.
But for containers with equivalent keys a single-linked list can degrade badly
when a large number of elements with equivalent keys are inserted. I think it's
reasonable to assume that users who choose to use `unordered_multiset` or
`unordered_multimap` do so because they are likely to insert elements with
equivalent keys. So I have used an alternative data structure that doesn't
degrade, at the expense of an extra pointer per node.
This works by adding storing a circular linked list for each group of equivalent
nodes in reverse order. This allows quick navigation to the end of a group (since
the first element points to the last) and can be quickly updated when elements
are inserted or erased. The main disadvantage of this approach is some hairy code
for erasing elements.
[h2 Number of Buckets]
There are two popular methods for choosing the number of buckets in a hash
table. One is to have a prime number of buckets, another is to use a power
of 2.
Using a prime number of buckets, and choosing a bucket by using the modulus
of the hash function's result will usually give a good result. The downside
is that the required modulus operation is fairly expensive.
Using a power of 2 allows for much quicker selection of the bucket
to use, but at the expense of loosing the upper bits of the hash value.
For some specially designed hash functions it is possible to do this and
still get a good result but as the containers can take arbitrary hash
functions this can't be relied on.
To avoid this a transformation could be applied to the hash function, for an
example see __wang__. Unfortunately, a transformation like Wang's requires
knowledge of the number of bits in the hash value, so it isn't portable enough.
This leaves more expensive methods, such as Knuth's Multiplicative Method
(mentioned in Wang's article). These don't tend to work as well as taking the
modulus of a prime, and the extra computation required might negate
efficiency advantage of power of 2 hash tables.
So, this implementation uses a prime number for the hash table size.
[h2 Equality operators]
`operator==` and `operator!=` are not included in the standard, but I've
added them as I think they could be useful and can be implemented
fairly efficiently. They are specified differently to the other standard
containers, comparing keys using the equality predicate rather than
`operator==`.
It's also different to the proposal
[@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2944.pdf n2944].
which uses the equality operators for the whole of `value_type`. This
implementation just uses the key equality function for the key,
and `mapped_type`'s equality operator in `unordered_map` and
`unordered_multimap` for the mapped part of the element.
Also, in `unordered_multimap`, the mapped values for a group of elements with
equivalent keys are only considered equal if they are in the same order,
in n2944 they just need to be a permutation of each other. Since the
order of elements with equal keys is now defined to be stable, it seems to me
that their order can be considered part of the container's value.
[h2 Active Issues and Proposals]
[h3 C++0x allocators]
Recent drafts have included an overhaul of the allocators, but this was
dependent on concepts which are no longer in the standard.
[@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2946.pdf n2946]
attempts to respecify them without concepts. I'll try to implement this (or
an appropriate later version) in a future version of boost, possibly changed
a little to accomodate non-C++0x compilers.
[h3 Swapping containers with unequal allocators]
It isn't clear how to swap containers when their allocators aren't equal.
This is
[@http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#431
Issue 431: Swapping containers with unequal allocators]. This has been resolved
with the new allocator specification, so this should be fixed when
support is added.
[h3 Are insert and erase stable for unordered_multiset and unordered_multimap?]
It wan't specified if `unordered_multiset` and `unordered_multimap` preserve the order
of elements with equivalent keys (i.e. if they're stable under `insert` and `erase`).
Since [@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2691.pdf
n2691] it's been specified that they do and this implementation follows that.
[endsect]
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# Refactoring Roadmap
[Proof of concept](https://github.com/joaquintides/fca_unordered) implementation for a fast closed-addressing implementation.
## Plan of Refactoring
* remove `ptr_node` and `ptr_bucket`
* see if the code can survive a lack of the `extra_node` or maybe we hard-code it in
* implement bucket groups as they are in `fca` but don't use them directly yet, add alongside the `buckets_` data member in `struct table`
* try to remove `bucket_info_` from the node structure (breaks all call-sites that use `get_bucket()` and dependents)
* make sure `fca` can successfully handle multi-variants at this stage + supports mutable iterators for `map`/`multimap`
* do a hard-break:
* update code to no longer use one single linked list across all buckets (each bucket contains its own unique list)
* integrate the `bucket_group<Node>` structure into the `table` (update iterator call-sites to include `bucket_iterator`s)
Blockers:
* how to handle `multi` variants with new `fca` prototype
## Implementation Differences
### Unordered
### Node Type
Bullet Points:
* reify node type into a single one
* come up with implementation for multi- variants
* code that touches `get_bucket()` and `*_in_group()` member functions may need updating
There are two node types in Unordered, `struct node` and `struct ptr_node`, and the node type is selected conditionally based on the Allocator's pointer type:
```c++
template <typename A, typename T, typename NodePtr, typename BucketPtr>
struct pick_node2
{
typedef boost::unordered::detail::node<A, T> node;
// ...
};
template <typename A, typename T>
struct pick_node2<A, T, boost::unordered::detail::ptr_node<T>*,
boost::unordered::detail::ptr_bucket*>
{
typedef boost::unordered::detail::ptr_node<T> node;
// ...
};
template <typename A, typename T> struct pick_node
{
typedef typename boost::remove_const<T>::type nonconst;
typedef boost::unordered::detail::allocator_traits<
typename boost::unordered::detail::rebind_wrap<A,
boost::unordered::detail::ptr_node<nonconst> >::type>
tentative_node_traits;
typedef boost::unordered::detail::allocator_traits<
typename boost::unordered::detail::rebind_wrap<A,
boost::unordered::detail::ptr_bucket>::type>
tentative_bucket_traits;
typedef pick_node2<A, nonconst, typename tentative_node_traits::pointer,
typename tentative_bucket_traits::pointer>
pick;
typedef typename pick::node node;
typedef typename pick::bucket bucket;
typedef typename pick::link_pointer link_pointer;
};
```
The node types are identical in terms of interface and the only difference is that `node` is chosen when the Allocator uses fancy pointers and `ptr_node` is chosen when the Allocator's pointer type is `T*`.
Nodes in Unorderd store `bucket_info_`:
```cpp
template <typename A, typename T>
struct node : boost::unordered::detail::value_base<T>
{
link_pointer next_;
std::size_t bucket_info_;
node() : next_(), bucket_info_(0) {}
// ...
};
```
`bucket_info_` maps each node back to its corresponding bucket via the member function:
```cpp
std::size_t get_bucket() const
{
return bucket_info_ & ((std::size_t)-1 >> 1);
}
```
`bucket_info_` is also used to demarcate the start of equivalent nodes in the containers via:
```cpp
// Note that nodes start out as the first in their group, as `bucket_info_` defaults to 0.
std::size_t is_first_in_group() const
{ return !(bucket_info_ & ~((std::size_t)-1 >> 1)); }
void set_first_in_group()
{ bucket_info_ = bucket_info_ & ((std::size_t)-1 >> 1); }
void reset_first_in_group()
{ bucket_info_ = bucket_info_ | ~((std::size_t)-1 >> 1); }
```
A goal of refactoring is to simply have one node type:
```cpp
template<class T>
struct node {
node *next;
T value;
};
```
that is used unconditionally. This also requires updating the code that touches the `bucket_info_` along with the code that that touches the `*_in_group()` member functions.
### Bucket Type
Bullet points:
* reify bucket structure into a single one
* figure out how to add `bucket_group`s to the table struct
Buckets are similar to nodes in that there are two variations: `template<class NodePointer> struct bucket` and `struct ptr_bucket`.
The buckets exist to contain a pointer to a node, however they contain an `enum { extra_node = true };` or `enum { extra_node = false }` to determine whether or not the code should explicitly allocate a default constructed node whose address assigned as the dummy node at the end of the bucket array.
`extra_node` is used in the creation and deletion of the bucket array but it is not inherently clear what its intended purpose is.
### Iterators
Iterators are currently templated on the type of Node they store. Because `fca` constructs iterators with two arguments, all the call-sites that instantiate iterators will need to be updated but this a straight-forward mechanical change.
Iterators are selected, as of now, via the `detail::map` and `detail::set` class templates.
For example, for `unordered_map`, `iterator` is defined as:
```cpp
typedef boost::unordered::detail::map<A, K, T, H, P> types;
typedef typename types::table table;
typedef typename table::iterator iterator;
```
The iterator is a member typedef of the `table` which is `types::table`. Examining `types` (aka `detail::map<...>`), we see:
```cpp
template <typename A, typename K, typename M, typename H, typename P>
struct map {
// ...
typedef boost::unordered::detail::table<types> table;
// ...
};
```
Examining the `detail::table<types>` struct, we see:
```cpp
template <typename Types>
struct table {
// ...
typedef typename Types::iterator iterator;
// ...
}
```
Collapsing all of this, we see that our iterator types are defined here:
```cpp
template <typename A, typename K, typename M, typename H, typename P>
struct map
{
// ...
typedef boost::unordered::detail::pick_node<A, value_type> pick;
typedef typename pick::node node;
typedef boost::unordered::iterator_detail::iterator<node> iterator;
typedef boost::unordered::iterator_detail::c_iterator<node> c_iterator;
typedef boost::unordered::iterator_detail::l_iterator<node> l_iterator;
typedef boost::unordered::iterator_detail::cl_iterator<node>
cl_iterator;
// ...
};
```
This is similarly designed for `detail::set`:
```cpp
typedef boost::unordered::iterator_detail::c_iterator<node> iterator;
typedef boost::unordered::iterator_detail::c_iterator<node> c_iterator;
typedef boost::unordered::iterator_detail::cl_iterator<node> l_iterator;
typedef boost::unordered::iterator_detail::cl_iterator<node>
cl_iterator;
```
The only difference here is that `set::iterator` is always a `c_iterator`, a `const_iterator` type.
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// Copyright 2006-2007 Daniel James.
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#include <boost/unordered_map.hpp>
#include <boost/detail/lightweight_test.hpp>
#include <boost/algorithm/string/predicate.hpp>
#include "../../examples/fnv1.hpp"
//[case_insensitive_functions
struct iequal_to
: std::binary_function<std::string, std::string, bool>
{
bool operator()(std::string const& x,
std::string const& y) const
{
return boost::algorithm::iequals(x, y, std::locale());
}
};
struct ihash
: std::unary_function<std::string, std::size_t>
{
std::size_t operator()(std::string const& x) const
{
std::size_t seed = 0;
std::locale locale;
for(std::string::const_iterator it = x.begin();
it != x.end(); ++it)
{
boost::hash_combine(seed, std::toupper(*it, locale));
}
return seed;
}
};
//]
int main() {
//[case_sensitive_dictionary_fnv
boost::unordered_map<std::string, int, hash::fnv_1>
dictionary;
//]
BOOST_TEST(dictionary.empty());
dictionary["one"] = 1;
BOOST_TEST(dictionary.size() == 1);
BOOST_TEST(dictionary.find("ONE") == dictionary.end());
dictionary.insert(std::make_pair("ONE", 2));
BOOST_TEST(dictionary.size() == 2);
BOOST_TEST(dictionary.find("ONE") != dictionary.end() &&
dictionary.find("ONE")->first == "ONE" &&
dictionary.find("ONE")->second == 2);
dictionary["One"] = 3;
BOOST_TEST(dictionary.size() == 3);
BOOST_TEST(dictionary.find("One") != dictionary.end() &&
dictionary.find("One")->first == "One" &&
dictionary.find("One")->second == 3);
dictionary["two"] = 4;
BOOST_TEST(dictionary.size() == 4);
BOOST_TEST(dictionary.find("Two") == dictionary.end() &&
dictionary.find("two") != dictionary.end() &&
dictionary.find("two")->second == 4);
//[case_insensitive_dictionary
boost::unordered_map<std::string, int, ihash, iequal_to>
idictionary;
//]
BOOST_TEST(idictionary.empty());
idictionary["one"] = 1;
BOOST_TEST(idictionary.size() == 1);
BOOST_TEST(idictionary.find("ONE") != idictionary.end() &&
idictionary.find("ONE") == idictionary.find("one"));
idictionary.insert(std::make_pair("ONE", 2));
BOOST_TEST(idictionary.size() == 1);
BOOST_TEST(idictionary.find("ONE") != idictionary.end() &&
idictionary.find("ONE")->first == "one" &&
idictionary.find("ONE")->second == 1);
idictionary["One"] = 3;
BOOST_TEST(idictionary.size() == 1);
BOOST_TEST(idictionary.find("ONE") != idictionary.end() &&
idictionary.find("ONE")->first == "one" &&
idictionary.find("ONE")->second == 3);
idictionary["two"] = 4;
BOOST_TEST(idictionary.size() == 2);
BOOST_TEST(idictionary.find("two") != idictionary.end() &&
idictionary.find("TWO")->first == "two" &&
idictionary.find("Two")->second == 4);
return boost::report_errors();
}
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// Copyright 2006-2009 Daniel James.
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//[intro_example1_1
#include <boost/unordered_map.hpp>
#include <boost/foreach.hpp>
#include <cassert>
#include <iostream>
//]
int main() {
//[intro_example1_2
typedef boost::unordered_map<std::string, int> map;
map x;
x["one"] = 1;
x["two"] = 2;
x["three"] = 3;
assert(x.at("one") == 1);
assert(x.find("missing") == x.end());
//]
//[intro_example1_3
BOOST_FOREACH(map::value_type i, x) {
std::cout<<i.first<<","<<i.second<<"\n";
}
//]
}
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// Copyright 2006-2009 Daniel James.
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#include <boost/unordered_set.hpp>
#include <boost/detail/lightweight_test.hpp>
//[point_example1
struct point {
int x;
int y;
};
bool operator==(point const& p1, point const& p2)
{
return p1.x == p2.x && p1.y == p2.y;
}
struct point_hash
: std::unary_function<point, std::size_t>
{
std::size_t operator()(point const& p) const
{
std::size_t seed = 0;
boost::hash_combine(seed, p.x);
boost::hash_combine(seed, p.y);
return seed;
}
};
boost::unordered_multiset<point, point_hash> points;
//]
int main() {
point x[] = {{1,2}, {3,4}, {1,5}, {1,2}};
for(int i = 0; i < sizeof(x) / sizeof(point); ++i)
points.insert(x[i]);
BOOST_TEST(points.count(x[0]) == 2);
BOOST_TEST(points.count(x[1]) == 1);
point y = {10, 2};
BOOST_TEST(points.count(y) == 0);
return boost::report_errors();
}
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// Copyright 2006-2009 Daniel James.
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#include <boost/unordered_set.hpp>
#include <boost/functional/hash.hpp>
#include <boost/detail/lightweight_test.hpp>
//[point_example2
struct point {
int x;
int y;
};
bool operator==(point const& p1, point const& p2)
{
return p1.x == p2.x && p1.y == p2.y;
}
std::size_t hash_value(point const& p) {
std::size_t seed = 0;
boost::hash_combine(seed, p.x);
boost::hash_combine(seed, p.y);
return seed;
}
// Now the default function objects work.
boost::unordered_multiset<point> points;
//]
int main() {
point x[] = {{1,2}, {3,4}, {1,5}, {1,2}};
for(int i = 0; i < sizeof(x) / sizeof(point); ++i)
points.insert(x[i]);
BOOST_TEST(points.count(x[0]) == 2);
BOOST_TEST(points.count(x[1]) == 1);
point y = {10, 2};
BOOST_TEST(points.count(y) == 0);
return boost::report_errors();
}
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= Boost.Unordered
:toc: left
:toclevels: 3
:idprefix:
:docinfo: private-footer
:source-highlighter: rouge
:source-language: c++
:nofooter:
:sectlinks:
:leveloffset: +1
include::unordered/intro.adoc[]
include::unordered/buckets.adoc[]
include::unordered/benchmarks.adoc[]
include::unordered/hash_equality.adoc[]
include::unordered/comparison.adoc[]
include::unordered/compliance.adoc[]
include::unordered/rationale.adoc[]
include::unordered/ref.adoc[]
include::unordered/changes.adoc[]
include::unordered/bibliography.adoc[]
include::unordered/copyright.adoc[]
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[/ Copyright 2006-2008 Daniel James.
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) ]
[library Boost.Unordered
[quickbook 1.4]
[authors [James, Daniel]]
[copyright 2003 2004 Jeremy B. Maitin-Shepard]
[copyright 2005 2006 2007 2008 Daniel James]
[purpose std::tr1 compliant hash containers]
[id unordered]
[dirname unordered]
[license
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE_1_0.txt or copy at
[@http://www.boost.org/LICENSE_1_0.txt]
]
]
[template diagram[name] '''<inlinemediaobject>
<imageobject role="html">
<imagedata align = "center" fileref="../../libs/unordered/doc/diagrams/'''[name]'''.png"></imagedata>
</imageobject>
<imageobject role="print">
<imagedata align = "center" fileref="../../libs/unordered/doc/diagrams/'''[name]'''.svg"></imagedata>
</imageobject>
</inlinemediaobject>''']
[include:unordered intro.qbk]
[include:unordered buckets.qbk]
[include:unordered hash_equality.qbk]
[include:unordered comparison.qbk]
[include:unordered rationale.qbk]
[include:unordered changes.qbk]
[xinclude ref.xml]
[xinclude bibliography.xml]
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[#benchmarks]
:idprefix: benchmarks_
:imagesdir: ../diagrams
= Benchmarks
All benchmarks were created using `unordered_set<unsigned int>` (non-duplicate) and `unordered_multiset<unsigned int>` (duplicate). The source code can be https://github.com/joaquintides/boost_unordered_benchmark[found here].
The insertion benchmarks insert `n` random values, where `n` is between 10,000 and 3 million. For the duplicated benchmarks, the same random values are repeated an average of 5 times.
The erasure benchmarks erase all `n` elements randomly until the container is empty.
The successful lookup benchmarks are done by looking up all `n` values, in the their original insertion order.
The unsuccessful lookup benchmarks use `n` randomly generated integers but using a different seed value.
== GCC 11 + libstdc++-v3
=== Insertion
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/gcc/running insertion.xlsx.practice.png[width=250,link=../diagrams/benchmarks/gcc/running insertion.xlsx.practice.png,window=_blank]
|image::benchmarks/gcc/running%20insertion.xlsx.practice non-unique.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice non-unique.png,window=_blank]
|image::benchmarks/gcc/running%20insertion.xlsx.practice non-unique 5.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice non-unique 5.png,window=_blank]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements +
max load factor 5
|===
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/gcc/running%20insertion.xlsx.practice norehash.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice norehash.png,window=_blank]
|image::benchmarks/gcc/running%20insertion.xlsx.practice norehash non-unique.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice norehash non-unique.png,window=_blank]
|image::benchmarks/gcc/running%20insertion.xlsx.practice norehash non-unique 5.png[width=250,link=../diagrams/benchmarks/gcc/running%20insertion.xlsx.practice norehash non-unique 5.png,window=_blank]
h|non-duplicate elements, +
prior `reserve`
h|duplicate elements, +
prior `reserve`
h|duplicate elements, +
max load factor 5, +
prior `reserve`
|===
=== Erasure
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/gcc/scattered%20erasure.xlsx.practice.png[width=250,link=../diagrams/benchmarks/gcc/scattered%20erasure.xlsx.practice.png,window=_blank]
|image::benchmarks/gcc/scattered%20erasure.xlsx.practice non-unique.png[width=250,link=../diagrams/benchmarks/gcc/scattered%20erasure.xlsx.practice non-unique.png,window=_blank]
|image::benchmarks/gcc/scattered%20erasure.xlsx.practice non-unique 5.png[width=250,link=../diagrams/benchmarks/gcc/scattered%20erasure.xlsx.practice non-unique 5.png,window=_blank]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements +
max load factor 5
|===
=== Successful Lookup
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice.png]
|image::benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice non-unique.png]
|image::benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20successful%20looukp.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
=== Unsuccessful lookup
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice.png]
|image::benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png]
|image::benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/gcc/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
== Clang 12 + libc++
=== Insertion
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice.png[width=250, window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice.png]
|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice non-unique.png[width=250, window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice non-unique.png]
|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice non-unique 5.png[width=250, window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash.png]
|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash non-unique.png]
|image::benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/running%20insertion.xlsx.practice norehash non-unique 5.png]
h|non-duplicate elements, +
prior `reserve`
h|duplicate elements, +
prior `reserve`
h|duplicate elements, +
max load factor 5, +
prior `reserve`
|===
=== Erasure
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice.png]
|image::benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice non-unique.png]
|image::benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20erasure.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
=== Successful lookup
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice.png]
|image::benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice non-unique.png]
|image::benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20successful%20looukp.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
=== Unsuccessful lookup
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice.png]
|image::benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png]
|image::benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/clang_libcpp/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
== Visual Studio 2019 + Dinkumware
=== Insertion
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/vs/running%20insertion.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice.png]
|image::benchmarks/vs/running%20insertion.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice non-unique.png]
|image::benchmarks/vs/running%20insertion.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/vs/running%20insertion.xlsx.practice norehash.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice norehash.png]
|image::benchmarks/vs/running%20insertion.xlsx.practice norehash non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice norehash non-unique.png]
|image::benchmarks/vs/running%20insertion.xlsx.practice norehash non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/running%20insertion.xlsx.practice norehash non-unique 5.png]
h|non-duplicate elements, +
prior `reserve`
h|duplicate elements, +
prior `reserve`
h|duplicate elements, +
max load factor 5, +
prior `reserve`
|===
=== Erasure
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/vs/scattered%20erasure.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20erasure.xlsx.practice.png]
|image::benchmarks/vs/scattered%20erasure.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20erasure.xlsx.practice non-unique.png]
|image::benchmarks/vs/scattered%20erasure.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20erasure.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
=== Successful lookup
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/vs/scattered%20successful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20successful%20looukp.xlsx.practice.png]
|image::benchmarks/vs/scattered%20successful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20successful%20looukp.xlsx.practice non-unique.png]
|image::benchmarks/vs/scattered%20successful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20successful%20looukp.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
=== Unsuccessful lookup
[caption=]
[cols="3*^.^a", frame=all, grid=all]
|===
|image::benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice.png]
|image::benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice non-unique.png]
|image::benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png[width=250,window=_blank,link=../diagrams/benchmarks/vs/scattered%20unsuccessful%20looukp.xlsx.practice non-unique 5.png]
h|non-duplicate elements
h|duplicate elements
h|duplicate elements, +
max load factor 5
|===
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[#bibliography]
:idprefix: bibliography_
= Bibliography
* _C/C++ Users Journal_. February, 2006. Pete Becker. http://www.ddj.com/cpp/184402066[STL and TR1: Part III - Unordered containers^]. +
An introducation to the standard unordered containers.
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[#buckets]
:idprefix: buckets_
:imagesdir: ../diagrams
= The Data Structure
The containers are made up of a number of 'buckets', each of which can contain
any number of elements. For example, the following diagram shows an <<unordered_set,unordered_set>> with 7 buckets containing 5 elements, `A`,
`B`, `C`, `D` and `E` (this is just for illustration, containers will typically
have more buckets).
image::buckets.png[]
In order to decide which bucket to place an element in, the container applies
the hash function, `Hash`, to the element's key (for `unordered_set` and
`unordered_multiset` the key is the whole element, but is referred to as the key
so that the same terminology can be used for sets and maps). This returns a
value of type `std::size_t`. `std::size_t` has a much greater range of values
then the number of buckets, so the container applies another transformation to
that value to choose a bucket to place the element in.
Retrieving the elements for a given key is simple. The same process is applied
to the key to find the correct bucket. Then the key is compared with the
elements in the bucket to find any elements that match (using the equality
predicate `Pred`). If the hash function has worked well the elements will be
evenly distributed amongst the buckets so only a small number of elements will
need to be examined.
There is <<hash_equality, more information on hash functions and
equality predicates in the next section>>.
You can see in the diagram that `A` & `D` have been placed in the same bucket.
When looking for elements in this bucket up to 2 comparisons are made, making
the search slower. This is known as a collision. To keep things fast we try to
keep collisions to a minimum.
[caption=, title='Table {counter:table-counter}. Methods for Accessing Buckets']
[cols="1,.^1", frame=all, grid=rows]
|===
|Method |Description
|`size_type bucket_count() const`
|The number of buckets.
|`size_type max_bucket_count() const`
|An upper bound on the number of buckets.
|`size_type bucket_size(size_type n) const`
|The number of elements in bucket `n`.
|`size_type bucket(key_type const& k) const`
|Returns the index of the bucket which would contain `k`.
|`local_iterator begin(size_type n)`
1.6+|Return begin and end iterators for bucket `n`.
|`local_iterator end(size_type n)`
|`const_local_iterator begin(size_type n) const`
|`const_local_iterator end(size_type n) const`
|`const_local_iterator cbegin(size_type n) const`
|`const_local_iterator cend(size_type n) const`
|===
== Controlling the number of buckets
As more elements are added to an unordered associative container, the number
of elements in the buckets will increase causing performance to degrade.
To combat this the containers increase the bucket count as elements are inserted.
You can also tell the container to change the bucket count (if required) by
calling `rehash`.
The standard leaves a lot of freedom to the implementer to decide how the
number of buckets is chosen, but it does make some requirements based on the
container's 'load factor', the average number of elements per bucket.
Containers also have a 'maximum load factor' which they should try to keep the
load factor below.
You can't control the bucket count directly but there are two ways to
influence it:
* Specify the minimum number of buckets when constructing a container or when calling `rehash`.
* Suggest a maximum load factor by calling `max_load_factor`.
`max_load_factor` doesn't let you set the maximum load factor yourself, it just
lets you give a _hint_. And even then, the standard doesn't actually
require the container to pay much attention to this value. The only time the
load factor is _required_ to be less than the maximum is following a call to
`rehash`. But most implementations will try to keep the number of elements
below the max load factor, and set the maximum load factor to be the same as
or close to the hint - unless your hint is unreasonably small or large.
[caption=, title='Table {counter:table-counter}. Methods for Controlling Bucket Size']
[cols="1,.^1", frame=all, grid=rows]
|===
|Method |Description
|`X(size_type n)`
|Construct an empty container with at least `n` buckets (`X` is the container type).
|`X(InputIterator i, InputIterator j, size_type n)`
|Construct an empty container with at least `n` buckets and insert elements from the range `[i, j)` (`X` is the container type).
|`float load_factor() const`
|The average number of elements per bucket.
|`float max_load_factor() const`
|Returns the current maximum load factor.
|`float max_load_factor(float z)`
|Changes the container's maximum load factor, using `z` as a hint.
|`void rehash(size_type n)`
|Changes the number of buckets so that there at least `n` buckets, and so that the load factor is less than the maximum load factor.
|===
== Iterator Invalidation
It is not specified how member functions other than `rehash` and `reserve` affect
the bucket count, although `insert` is only allowed to invalidate iterators
when the insertion causes the load factor to be greater than or equal to the
maximum load factor. For most implementations this means that `insert` will only
change the number of buckets when this happens. While iterators can be
invalidated by calls to `insert`, `rehash` and `reserve`, pointers and references to the
container's elements are never invalidated.
In a similar manner to using `reserve` for ``vector``s, it can be a good idea
to call `reserve` before inserting a large number of elements. This will get
the expensive rehashing out of the way and let you store iterators, safe in
the knowledge that they won't be invalidated. If you are inserting `n`
elements into container `x`, you could first call:
```
x.reserve(n);
```
Note:: `reserve(n)` reserves space for at least `n` elements, allocating enough buckets
so as to not exceed the maximum load factor.
+
Because the maximum load factor is defined as the number of elements divided by the total
number of available buckets, this function is logically equivalent to:
+
```
x.rehash(std::ceil(n / x.max_load_factor()))
```
+
See the <<unordered_map_rehash,reference for more details>> on the `rehash` function.
== Fast Closed Addressing Implementation
++++
<style>
.imageblock > .title {
text-align: inherit;
}
</style>
++++
Boost.Unordered sports one of the fastest implementations of closed addressing, also commonly known as https://en.wikipedia.org/wiki/Hash_table#Separate_chaining[separate chaining]. An example figure representing the data structure is below:
[#img-bucket-groups,.text-center]
.A simple bucket group approach
image::bucket-groups.png[align=center]
An array of "buckets" is allocated and each bucket in turn points to its own individual linked list. This makes meeting the standard requirements of bucket iteration straight-forward. Unfortunately, iteration of the entire container is often times slow using this layout as each bucket must be examined for occupancy, yielding a time complexity of `O(bucket_count() + size())` when the standard requires complexity to be `O(size())`.
Canonical standard implementations will wind up looking like the diagram below:
[.text-center]
.The canonical standard approach
image::singly-linked.png[align=center,link=../diagrams/singly-linked.png,window=_blank]
It's worth noting that this approach is only used by pass:[libc++] and pass:[libstdc++]; the MSVC Dinkumware implementation uses a different one. A more detailed analysis of the standard containers can be found http://bannalia.blogspot.com/2013/10/implementation-of-c-unordered.html[here].
This unusually laid out data structure is chosen to make iteration of the entire container efficient by inter-connecting all of the nodes into a singly-linked list. One might also notice that buckets point to the node _before_ the start of the bucket's elements. This is done so that removing elements from the list can be done efficiently without introducing the need for a doubly-linked list. Unfortunately, this data structure introduces a guaranteed extra indirection. For example, to access the first element of a bucket, something like this must be done:
```c++
auto const idx = get_bucket_idx(hash_function(key));
node* p = buckets[idx]; // first load
node* n = p->next; // second load
if (n && is_in_bucket(n, idx)) {
value_type const& v = *n; // third load
// ...
}
```
With a simple bucket group layout, this is all that must be done:
```c++
auto const idx = get_bucket_idx(hash_function(key));
node* n = buckets[idx]; // first load
if (n) {
value_type const& v = *n; // second load
// ...
}
```
In practice, the extra indirection can have a dramatic performance impact to common operations such as `insert`, `find` and `erase`. But to keep iteration of the container fast, Boost.Unordered introduces a novel data structure, a "bucket group". A bucket group is a fixed-width view of a subsection of the buckets array. It contains a bitmask (a `std::size_t`) which it uses to track occupancy of buckets and contains two pointers so that it can form a doubly-linked list with non-empty groups. An example diagram is below:
[#img-fca-layout]
.The new layout used by Boost
image::fca.png[align=center]
Thus container-wide iteration is turned into traversing the non-empty bucket groups (an operation with constant time complexity) which reduces the time complexity back to `O(size())`. In total, a bucket group is only 4 words in size and it views `sizeof(std::size_t) * CHAR_BIT` buckets meaning that for all common implementations, there's only 4 bits of space overhead per bucket introduced by the bucket groups.
For more information on implementation rationale, read the <<Implementation Rationale, corresponding section>>.
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[#changes]
= Change Log
:idprefix: changes_
:svn-ticket-url: https://svn.boost.org/trac/boost/ticket
:github-pr-url: https://github.com/boostorg/unordered/pull
:cpp: C++
== Release 1.80.0 - Major update
* Refactor internal implementation to be dramatically faster
* Allow `final` Hasher and KeyEqual objects
* Update documentation, adding benchmark graphs and notes on the new internal
data structures
== Release 1.79.0
* Improved {cpp}20 support:
** All containers have been updated to support
heterogeneous `count`, `equal_range` and `find`.
** All containers now implement the member function `contains`.
** `erase_if` has been implemented for all containers.
* Improved {cpp}23 support:
** All containers have been updated to support
heterogeneous `erase` and `extract`.
* Changed behavior of `reserve` to eagerly
allocate ({github-pr-url}/59[PR#59^]).
* Various warning fixes in the test suite.
* Update code to internally use `boost::allocator_traits`.
* Switch to Fibonacci hashing.
* Update documentation to be written in AsciiDoc instead of QuickBook.
== Release 1.67.0
* Improved {cpp}17 support:
** Add template deduction guides from the standard.
** Use a simple implementation of `optional` in node handles, so
that they're closer to the standard.
** Add missing `noexcept` specifications to `swap`, `operator=`
and node handles, and change the implementation to match.
Using `std::allocator_traits::is_always_equal`, or our own
implementation when not available, and
`boost::is_nothrow_swappable` in the implementation.
* Improved {cpp}20 support:
** Use `boost::to_address`, which has the proposed {cpp}20 semantics,
rather than the old custom implementation.
* Add `element_type` to iterators, so that `std::pointer_traits`
will work.
* Use `std::piecewise_construct` on recent versions of Visual {cpp},
and other uses of the Dinkumware standard library,
now using Boost.Predef to check compiler and library versions.
* Use `std::iterator_traits` rather than the boost iterator traits
in order to remove dependency on Boost.Iterator.
* Remove iterators' inheritance from `std::iterator`, which is
deprecated in {cpp}17, thanks to Daniela Engert
({github-pr-url}/7[PR#7^]).
* Stop using `BOOST_DEDUCED_TYPENAME`.
* Update some Boost include paths.
* Rename some internal methods, and variables.
* Various testing improvements.
* Miscellaneous internal changes.
== Release 1.66.0
* Simpler move construction implementation.
* Documentation fixes ({github-pr-url}/6[GitHub #6^]).
== Release 1.65.0
* Add deprecated attributes to `quick_erase` and `erase_return_void`.
I really will remove them in a future version this time.
* Small standards compliance fixes:
** `noexpect` specs for `swap` free functions.
** Add missing `insert(P&&)` methods.
== Release 1.64.0
* Initial support for new {cpp}17 member functions:
`insert_or_assign` and `try_emplace` in `unordered_map`,
* Initial support for `merge` and `extract`.
Does not include transferring nodes between
`unordered_map` and `unordered_multimap` or between `unordered_set` and
`unordered_multiset` yet. That will hopefully be in the next version of
Boost.
== Release 1.63.0
* Check hint iterator in `insert`/`emplace_hint`.
* Fix some warnings, mostly in the tests.
* Manually write out `emplace_args` for small numbers of arguments -
should make template error messages a little more bearable.
* Remove superfluous use of `boost::forward` in emplace arguments,
which fixes emplacing string literals in old versions of Visual {cpp}.
* Fix an exception safety issue in assignment. If bucket allocation
throws an exception, it can overwrite the hash and equality functions while
leaving the existing elements in place. This would mean that the function
objects wouldn't match the container elements, so elements might be in the
wrong bucket and equivalent elements would be incorrectly handled.
* Various reference documentation improvements.
* Better allocator support ({svn-ticket-url}/12459[#12459^]).
* Make the no argument constructors implicit.
* Implement missing allocator aware constructors.
* Fix assigning the hash/key equality functions for empty containers.
* Remove unary/binary_function from the examples in the documentation.
They are removed in {cpp}17.
* Support 10 constructor arguments in emplace. It was meant to support up to 10
arguments, but an off by one error in the preprocessor code meant it only
supported up to 9.
== Release 1.62.0
* Remove use of deprecated `boost::iterator`.
* Remove `BOOST_NO_STD_DISTANCE` workaround.
* Remove `BOOST_UNORDERED_DEPRECATED_EQUALITY` warning.
* Simpler implementation of assignment, fixes an exception safety issue
for `unordered_multiset` and `unordered_multimap`. Might be a little slower.
* Stop using return value SFINAE which some older compilers have issues
with.
== Release 1.58.0
* Remove unnecessary template parameter from const iterators.
* Rename private `iterator` typedef in some iterator classes, as it
confuses some traits classes.
* Fix move assignment with stateful, propagate_on_container_move_assign
allocators ({svn-ticket-url}/10777[#10777^]).
* Fix rare exception safety issue in move assignment.
* Fix potential overflow when calculating number of buckets to allocate
({github-pr-url}/4[GitHub #4^]).
== Release 1.57.0
* Fix the `pointer` typedef in iterators ({svn-ticket-url}/10672[#10672^]).
* Fix Coverity warning
({github-pr-url}/2[GitHub #2^]).
== Release 1.56.0
* Fix some shadowed variable warnings ({svn-ticket-url}/9377[#9377^]).
* Fix allocator use in documentation ({svn-ticket-url}/9719[#9719^]).
* Always use prime number of buckets for integers. Fixes performance
regression when inserting consecutive integers, although makes other
uses slower ({svn-ticket-url}/9282[#9282^]).
* Only construct elements using allocators, as specified in {cpp}11 standard.
== Release 1.55.0
* Avoid some warnings ({svn-ticket-url}/8851[#8851^], {svn-ticket-url}/8874[#8874^]).
* Avoid exposing some detail functions via. ADL on the iterators.
* Follow the standard by only using the allocators' construct and destroy
methods to construct and destroy stored elements. Don't use them for internal
data like pointers.
== Release 1.54.0
* Mark methods specified in standard as `noexpect`. More to come in the next
release.
* If the hash function and equality predicate are known to both have nothrow
move assignment or construction then use them.
== Release 1.53.0
* Remove support for the old pre-standard variadic pair constructors, and
equality implementation. Both have been deprecated since Boost 1.48.
* Remove use of deprecated config macros.
* More internal implementation changes, including a much simpler
implementation of `erase`.
== Release 1.52.0
* Faster assign, which assigns to existing nodes where possible, rather than
creating entirely new nodes and copy constructing.
* Fixed bug in `erase_range` ({svn-ticket-url}/7471[#7471^]).
* Reverted some of the internal changes to how nodes are created, especially
for {cpp}11 compilers. 'construct' and 'destroy' should work a little better
for {cpp}11 allocators.
* Simplified the implementation a bit. Hopefully more robust.
== Release 1.51.0
* Fix construction/destruction issue when using a {cpp}11 compiler with a
{cpp}03 allocator ({svn-ticket-url}/7100[#7100^]).
* Remove a `try..catch` to support compiling without exceptions.
* Adjust SFINAE use to try to support g++ 3.4 ({svn-ticket-url}/7175[#7175^]).
* Updated to use the new config macros.
== Release 1.50.0
* Fix equality for `unordered_multiset` and `unordered_multimap`.
* {svn-ticket-url}/6857[Ticket 6857^]:
Implement `reserve`.
* {svn-ticket-url}/6771[Ticket 6771^]:
Avoid gcc's `-Wfloat-equal` warning.
* {svn-ticket-url}/6784[Ticket 6784^]:
Fix some Sun specific code.
* {svn-ticket-url}/6190[Ticket 6190^]:
Avoid gcc's `-Wshadow` warning.
* {svn-ticket-url}/6905[Ticket 6905^]:
Make namespaces in macros compatible with `bcp` custom namespaces.
Fixed by Luke Elliott.
* Remove some of the smaller prime number of buckets, as they may make
collisions quite probable (e.g. multiples of 5 are very common because
we used base 10).
* On old versions of Visual {cpp}, use the container library's implementation
of `allocator_traits`, as it's more likely to work.
* On machines with 64 bit std::size_t, use power of 2 buckets, with Thomas
Wang's hash function to pick which one to use. As modulus is very slow
for 64 bit values.
* Some internal changes.
== Release 1.49.0
* Fix warning due to accidental odd assignment.
* Slightly better error messages.
== Release 1.48.0 - Major update
This is major change which has been converted to use Boost.Move's move
emulation, and be more compliant with the {cpp}11 standard. See the
xref:unordered.adoc#compliance[compliance section] for details.
The container now meets {cpp}11's complexity requirements, but to do so
uses a little more memory. This means that `quick_erase` and
`erase_return_void` are no longer required, they'll be removed in a
future version.
{cpp}11 support has resulted in some breaking changes:
* Equality comparison has been changed to the {cpp}11 specification.
In a container with equivalent keys, elements in a group with equal
keys used to have to be in the same order to be considered equal,
now they can be a permutation of each other. To use the old
behavior define the macro `BOOST_UNORDERED_DEPRECATED_EQUALITY`.
* The behaviour of swap is different when the two containers to be
swapped has unequal allocators. It used to allocate new nodes using
the appropriate allocators, it now swaps the allocators if
the allocator has a member structure `propagate_on_container_swap`,
such that `propagate_on_container_swap::value` is true.
* Allocator's `construct` and `destroy` functions are called with raw
pointers, rather than the allocator's `pointer` type.
* `emplace` used to emulate the variadic pair constructors that
appeared in early {cpp}0x drafts. Since they were removed it no
longer does so. It does emulate the new `piecewise_construct`
pair constructors - only you need to use
`boost::piecewise_construct`. To use the old emulation of
the variadic constructors define
`BOOST_UNORDERED_DEPRECATED_PAIR_CONSTRUCT`.
== Release 1.45.0
* Fix a bug when inserting into an `unordered_map` or `unordered_set` using
iterators which returns `value_type` by copy.
== Release 1.43.0
* {svn-ticket-url}/3966[Ticket 3966^]:
`erase_return_void` is now `quick_erase`, which is the
http://home.roadrunner.com/~hinnant/issue_review/lwg-active.html#579[
current forerunner for resolving the slow erase by iterator^], although
there's a strong possibility that this may change in the future. The old
method name remains for backwards compatibility but is considered deprecated
and will be removed in a future release.
* Use Boost.Exception.
* Stop using deprecated `BOOST_HAS_*` macros.
== Release 1.42.0
* Support instantiating the containers with incomplete value types.
* Reduced the number of warnings (mostly in tests).
* Improved codegear compatibility.
* {svn-ticket-url}/3693[Ticket 3693^]:
Add `erase_return_void` as a temporary workaround for the current
`erase` which can be inefficient because it has to find the next
element to return an iterator.
* Add templated find overload for compatible keys.
* {svn-ticket-url}/3773[Ticket 3773^]:
Add missing `std` qualifier to `ptrdiff_t`.
* Some code formatting changes to fit almost all lines into 80 characters.
== Release 1.41.0 - Major update
* The original version made heavy use of macros to sidestep some of the older
compilers' poor template support. But since I no longer support those
compilers and the macro use was starting to become a maintenance burden it
has been rewritten to use templates instead of macros for the implementation
classes.
* The container object is now smaller thanks to using `boost::compressed_pair`
for EBO and a slightly different function buffer - now using a bool instead
of a member pointer.
* Buckets are allocated lazily which means that constructing an empty container
will not allocate any memory.
== Release 1.40.0
* {svn-ticket-url}/2975[Ticket 2975^]:
Store the prime list as a preprocessor sequence - so that it will always get
the length right if it changes again in the future.
* {svn-ticket-url}/1978[Ticket 1978^]:
Implement `emplace` for all compilers.
* {svn-ticket-url}/2908[Ticket 2908^],
{svn-ticket-url}/3096[Ticket 3096^]:
Some workarounds for old versions of borland, including adding explicit
destructors to all containers.
* {svn-ticket-url}/3082[Ticket 3082^]:
Disable incorrect Visual {cpp} warnings.
* Better configuration for {cpp}0x features when the headers aren't available.
* Create less buckets by default.
== Release 1.39.0
* {svn-ticket-url}/2756[Ticket 2756^]: Avoid a warning
on Visual {cpp} 2009.
* Some other minor internal changes to the implementation, tests and
documentation.
* Avoid an unnecessary copy in `operator[]`.
* {svn-ticket-url}/2975[Ticket 2975^]: Fix length of
prime number list.
== Release 1.38.0
* Use link:../../../core/swap.html[`boost::swap`^].
* {svn-ticket-url}/2237[Ticket 2237^]:
Document that the equality and inequality operators are undefined for two
objects if their equality predicates aren't equivalent. Thanks to Daniel
Krügler.
* {svn-ticket-url}/1710[Ticket 1710^]:
Use a larger prime number list. Thanks to Thorsten Ottosen and Hervé
Brönnimann.
* Use
link:../../../type_traits/index.html[aligned storage^] to store the types.
This changes the way the allocator is used to construct nodes. It used to
construct the node with two calls to the allocator's `construct`
method - once for the pointers and once for the value. It now constructs
the node with a single call to construct and then constructs the value using
in place construction.
* Add support for {cpp}0x initializer lists where they're available (currently
only g++ 4.4 in {cpp}0x mode).
== Release 1.37.0
* Rename overload of `emplace` with hint, to `emplace_hint` as specified in
http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2008/n2691.pdf[n2691^].
* Provide forwarding headers at `<boost/unordered/unordered_map_fwd.hpp>` and
`<boost/unordered/unordered_set_fwd.hpp>`.
* Move all the implementation inside `boost/unordered`, to assist
modularization and hopefully make it easier to track Release subversion.
== Release 1.36.0
First official release.
* Rearrange the internals.
* Move semantics - full support when rvalue references are available, emulated
using a cut down version of the Adobe move library when they are not.
* Emplace support when rvalue references and variadic template are available.
* More efficient node allocation when rvalue references and variadic template
are available.
* Added equality operators.
== Boost 1.35.0 Add-on - 31st March 2008
Unofficial release uploaded to vault, to be used with Boost 1.35.0. Incorporated
many of the suggestions from the review.
* Improved portability thanks to Boost regression testing.
* Fix lots of typos, and clearer text in the documentation.
* Fix floating point to `std::size_t` conversion when calculating sizes from
the max load factor, and use `double` in the calculation for greater accuracy.
* Fix some errors in the examples.
== Review Version
Initial review version, for the review conducted from 7th December 2007 to
16th December 2007.
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[#comparison]
:idprefix: comparison_
= Comparison with Associative Containers
[caption=, title='Table {counter:table-counter} Interface differences']
[cols="1,1", frame=all, grid=rows]
|===
|Associative Containers |Unordered Associative Containers
|Parameterized by an ordering relation `Compare`
|Parameterized by a function object `Hash` and an equivalence relation `Pred`
|Keys can be compared using `key_compare` which is accessed by member function `key_comp()`, values can be compared using `value_compare` which is accessed by member function `value_comp()`.
|Keys can be hashed using `hasher` which is accessed by member function `hash_function()`, and checked for equality using `key_equal` which is accessed by member function `key_eq()`. There is no function object for compared or hashing values.
|Constructors have optional extra parameters for the comparison object.
|Constructors have optional extra parameters for the initial minimum number of buckets, a hash function and an equality object.
|Keys `k1`, `k2` are considered equivalent if `!Compare(k1, k2) && !Compare(k2, k1)`.
|Keys `k1`, `k2` are considered equivalent if `Pred(k1, k2)`
|Member function `lower_bound(k)` and `upper_bound(k)`
|No equivalent. Since the elements aren't ordered `lower_bound` and `upper_bound` would be meaningless.
|`equal_range(k)` returns an empty range at the position that `k` would be inserted if `k` isn't present in the container.
|`equal_range(k)` returns a range at the end of the container if `k` isn't present in the container. It can't return a positioned range as `k` could be inserted into multiple place. To find out the bucket that `k` would be inserted into use `bucket(k)`. But remember that an insert can cause the container to rehash - meaning that the element can be inserted into a different bucket.
|`iterator`, `const_iterator` are of the bidirectional category.
|`iterator`, `const_iterator` are of at least the forward category.
|Iterators, pointers and references to the container's elements are never invalidated.
|<<buckets_iterator_invalidation,Iterators can be invalidated by calls to insert or rehash>>. Pointers and references to the container's elements are never invalidated.
|Iterators iterate through the container in the order defined by the comparison object.
|Iterators iterate through the container in an arbitrary order, that can change as elements are inserted, although equivalent elements are always adjacent.
|No equivalent
|Local iterators can be used to iterate through individual buckets. (The order of local iterators and iterators aren't required to have any correspondence.)
|Can be compared using the `==`, `!=`, `<`, `\<=`, `>`, `>=` operators.
|Can be compared using the `==` and `!=` operators.
|
|When inserting with a hint, implementations are permitted to ignore the hint.
|`erase` never throws an exception
|The containers' hash or predicate function can throw exceptions from `erase`.
|===
---
[caption=, title='Table {counter:table-counter} Complexity Guarantees']
[cols="1,1,1", frame=all, grid=rows]
|===
|Operation |Associative Containers |Unordered Associative Containers
|Construction of empty container
|constant
|O(_n_) where _n_ is the minimum number of buckets.
|Construction of container from a range of _N_ elements
|O(_N log N_), O(_N_) if the range is sorted with `value_comp()`
|Average case O(_N_), worst case O(_N^2^_)
|Insert a single element
|logarithmic
|Average case constant, worst case linear
|Insert a single element with a hint
|Amortized constant if `t` elements inserted right after hint, logarithmic otherwise
|Average case constant, worst case linear (ie. the same as a normal insert).
|Inserting a range of _N_ elements
|_N_ log(`size()` + _N_)
|Average case O(_N_), worst case O(_N_ * `size()`)
|Erase by key, `k`
|O(log(`size()`) + `count(k)`)
|Average case: O(`count(k)`), Worst case: O(`size()`)
|Erase a single element by iterator
|Amortized constant
|Average case: O(1), Worst case: O(`size()`)
|Erase a range of _N_ elements
|O(log(`size()`) + _N_)
|Average case: O(_N_), Worst case: O(`size()`)
|Clearing the container
|O(`size()`)
|O(`size()`)
|Find
|logarithmic
|Average case: O(1), Worst case: O(`size()`)
|Count
|O(log(`size()`) + `count(k)`)
|Average case: O(1), Worst case: O(`size()`)
|`equal_range(k)`
|logarithmic
|Average case: O(`count(k)`), Worst case: O(`size()`)
|`lower_bound`,`upper_bound`
|logarithmic
|n/a
|===
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[#compliance]
= Standard Compliance
:idprefix: compliance_
:cpp: C++
The intent of Boost.Unordered is to implement a close (but imperfect)
implementation of the {cpp}17 standard, that will work with {cpp}98 upwards.
The wide compatibility does mean some comprimises have to be made.
With a compiler and library that fully support {cpp}11, the differences should
be minor.
== Move emulation
Support for move semantics is implemented using Boost.Move. If rvalue
references are available it will use them, but if not it uses a close,
but imperfect emulation. On such compilers:
* Non-copyable objects can be stored in the containers.
They can be constructed in place using `emplace`, or if they support
Boost.Move, moved into place.
* The containers themselves are not movable.
* Argument forwarding is not perfect.
== Use of allocators
{cpp}11 introduced a new allocator system. It's backwards compatible due to
the lax requirements for allocators in the old standard, but might need
some changes for allocators which worked with the old versions of the
unordered containers.
It uses a traits class, `allocator_traits` to handle the allocator
adding extra functionality, and making some methods and types optional.
During development a stable release of
`allocator_traits` wasn't available so an internal partial implementation
is always used in this version. Hopefully a future version will use the
standard implementation where available.
The member functions `construct`, `destroy` and `max_size` are now
optional, if they're not available a fallback is used.
A full implementation of `allocator_traits` requires sophisticated
member function detection so that the fallback is used whenever the
member function call is not well formed.
This requires support for SFINAE expressions, which are available on
GCC from version 4.4 and Clang.
On other compilers, there's just a test to see if the allocator has
a member, but no check that it can be called. So rather than using a
fallback there will just be a compile error.
`propagate_on_container_copy_assignment`,
`propagate_on_container_move_assignment`,
`propagate_on_container_swap` and
`select_on_container_copy_construction` are also supported.
Due to imperfect move emulation, some assignments might check
`propagate_on_container_copy_assignment` on some compilers and
`propagate_on_container_move_assignment` on others.
== Construction/Destruction using allocators
The following support is required for full use of {cpp}11 style
construction/destruction:
* Variadic templates.
* Piecewise construction of `std::pair`.
* Either `std::allocator_traits` or expression SFINAE.
This is detected using Boost.Config. The macro
`BOOST_UNORDERED_CXX11_CONSTRUCTION` will be set to 1 if it is found, or 0
otherwise.
When this is the case `allocator_traits::construct` and
`allocator_traits::destroy` will always be used, apart from when piecewise
constructing a `std::pair` using `boost::tuple` (see <<compliance_pairs,below>>), but that should be easily avoided.
When support is not available `allocator_traits::construct` and
`allocator_traits::destroy` are never called.
== Pointer Traits
`pointer_traits` aren't used. Instead, pointer types are obtained from
rebound allocators, this can cause problems if the allocator can't be
used with incomplete types. If `const_pointer` is not defined in the
allocator, `boost::pointer_to_other<pointer, const value_type>::type`
is used to obtain a const pointer.
== Pairs
Since the containers use `std::pair` they're limited to the version
from the current standard library. But since {cpp}11 ``std::pair``'s
`piecewise_construct` based constructor is very useful, `emplace`
emulates it with a `piecewise_construct` in the `boost::unordered`
namespace. So for example, the following will work:
[source,c++]
----
boost::unordered_multimap<std::string, std::complex> x;
x.emplace(
boost::unordered::piecewise_construct,
boost::make_tuple("key"), boost::make_tuple(1, 2));
----
Older drafts of the standard also supported variadic constructors
for `std::pair`, where the first argument would be used for the
first part of the pair, and the remaining for the second part.
== Miscellaneous
When swapping, `Pred` and `Hash` are not currently swapped by calling
`swap`, their copy constructors are used. As a consequence when swapping
an exception may be thrown from their copy constructor.
Variadic constructor arguments for `emplace` are only used when both
rvalue references and variadic template parameters are available.
Otherwise `emplace` can only take up to 10 constructors arguments.
-14
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@@ -1,14 +0,0 @@
[#copyright]
= Copyright and License
:idprefix: copyright_
*Daniel James*
Copyright (C) 2003, 2004 Jeremy B. Maitin-Shepard
Copyright (C) 2005-2008 Daniel James
Copyright (C) 2022 Christian Mazakas
Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
-149
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@@ -1,149 +0,0 @@
[#hash_equality]
:idprefix: hash_equality_
= Equality Predicates and Hash Functions
While the associative containers use an ordering relation to specify how the
elements are stored, the unordered associative containers use an equality
predicate and a hash function. For example, <<unordered_map,boost::unordered_map>>
is declared as:
```
template <
class Key, class Mapped,
class Hash = boost::hash<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<std::pair<Key const, Mapped> > >
class unordered_map;
```
The hash function comes first as you might want to change the hash function
but not the equality predicate. For example, if you wanted to use the
http://www.isthe.com/chongo/tech/comp/fnv/[FNV-1 hash^] you could write:
```
boost::unordered_map<std::string, int, hash::fnv_1>
dictionary;
```
There is an link:../../examples/fnv1.hpp[implementation of FNV-1^] in the examples directory.
If you wish to use a different equality function, you will also need to use a matching hash function. For example, to implement a case insensitive dictionary you need to define a case insensitive equality predicate and hash function:
```
struct iequal_to
{
bool operator()(std::string const& x,
std::string const& y) const
{
return boost::algorithm::iequals(x, y, std::locale());
}
};
struct ihash
{
std::size_t operator()(std::string const& x) const
{
std::size_t seed = 0;
std::locale locale;
for(std::string::const_iterator it = x.begin();
it != x.end(); ++it)
{
boost::hash_combine(seed, std::toupper(*it, locale));
}
return seed;
}
};
```
Which you can then use in a case insensitive dictionary:
```
boost::unordered_map<std::string, int, ihash, iequal_to>
idictionary;
```
This is a simplified version of the example at
link:../../examples/case_insensitive.hpp[/libs/unordered/examples/case_insensitive.hpp^] which supports other locales and string types.
CAUTION: Be careful when using the equality (`==`) operator with custom equality
predicates, especially if you're using a function pointer. If you compare two
containers with different equality predicates then the result is undefined.
For most stateless function objects this is impossible - since you can only
compare objects with the same equality predicate you know the equality
predicates must be equal. But if you're using function pointers or a stateful
equality predicate (e.g. `boost::function`) then you can get into trouble.
== Custom Types
Similarly, a custom hash function can be used for custom types:
```
struct point {
int x;
int y;
};
bool operator==(point const& p1, point const& p2)
{
return p1.x == p2.x && p1.y == p2.y;
}
struct point_hash
{
std::size_t operator()(point const& p) const
{
std::size_t seed = 0;
boost::hash_combine(seed, p.x);
boost::hash_combine(seed, p.y);
return seed;
}
};
boost::unordered_multiset<point, point_hash> points;
```
Since the default hash function is link:../../../container_hash/index.html[Boost.Hash^],
we can extend it to support the type so that the hash function doesn't need to be explicitly given:
```
struct point {
int x;
int y;
};
bool operator==(point const& p1, point const& p2)
{
return p1.x == p2.x && p1.y == p2.y;
}
std::size_t hash_value(point const& p) {
std::size_t seed = 0;
boost::hash_combine(seed, p.x);
boost::hash_combine(seed, p.y);
return seed;
}
// Now the default function objects work.
boost::unordered_multiset<point> points;
```
See the link:../../../container_hash/index.html[Boost.Hash documentation^] for more detail on how to
do this. Remember that it relies on extensions to the standard - so it
won't work for other implementations of the unordered associative containers,
you'll need to explicitly use Boost.Hash.
[caption=, title='Table {counter:table-counter} Methods for accessing the hash and equality functions']
[cols="1,.^1", frame=all, grid=rows]
|===
|Method |Description
|`hasher hash_function() const`
|Returns the container's hash function.
|`key_equal key_eq() const`
|Returns the container's key equality function..
|===
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@@ -1,116 +0,0 @@
[#intro]
= Introduction
:idprefix: intro_
:cpp: C++
For accessing data based on key lookup, the {cpp} standard library offers `std::set`,
`std::map`, `std::multiset` and `std::multimap`. These are generally
implemented using balanced binary trees so that lookup time has
logarithmic complexity. That is generally okay, but in many cases a
link:https://en.wikipedia.org/wiki/Hash_table[hash table^] can perform better, as accessing data has constant complexity,
on average. The worst case complexity is linear, but that occurs rarely and
with some care, can be avoided.
Also, the existing containers require a 'less than' comparison object
to order their elements. For some data types this is impossible to implement
or isn't practical. In contrast, a hash table only needs an equality function
and a hash function for the key.
With this in mind, unordered associative containers were added to the {cpp}
standard. This is an implementation of the containers described in {cpp}11,
with some <<compliance,deviations from the standard>> in
order to work with non-{cpp}11 compilers and libraries.
`unordered_set` and `unordered_multiset` are defined in the header
`<boost/unordered_set.hpp>`
[source,c++]
----
namespace boost {
template <
class Key,
class Hash = boost::hash<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<Key> >
class unordered_set;
template<
class Key,
class Hash = boost::hash<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<Key> >
class unordered_multiset;
}
----
`unordered_map` and `unordered_multimap` are defined in the header
`<boost/unordered_map.hpp>`
[source,c++]
----
namespace boost {
template <
class Key, class Mapped,
class Hash = boost::hash<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<std::pair<Key const, Mapped> > >
class unordered_map;
template<
class Key, class Mapped,
class Hash = boost::hash<Key>,
class Pred = std::equal_to<Key>,
class Alloc = std::allocator<std::pair<Key const, Mapped> > >
class unordered_multimap;
}
----
When using Boost.TR1, these classes are included from `<unordered_set>` and
`<unordered_map>`, with the classes added to the `std::tr1` namespace.
The containers are used in a similar manner to the normal associative
containers:
[source,cpp]
----
typedef boost::unordered_map<std::string, int> map;
map x;
x["one"] = 1;
x["two"] = 2;
x["three"] = 3;
assert(x.at("one") == 1);
assert(x.find("missing") == x.end());
----
But since the elements aren't ordered, the output of:
[source,c++]
----
BOOST_FOREACH(map::value_type i, x) {
std::cout<<i.first<<","<<i.second<<"\n";
}
----
can be in any order. For example, it might be:
[source]
----
two,2
one,1
three,3
----
To store an object in an unordered associative container requires both a
key equality function and a hash function. The default function objects in
the standard containers support a few basic types including integer types,
floating point types, pointer types, and the standard strings. Since
Boost.Unordered uses link:../../../container_hash/index.html[boost::hash^] it also supports some other types,
including standard containers. To use any types not supported by these methods
you have to extend Boost.Hash to support the type or use
your own custom equality predicates and hash functions. See the
<<hash_equality,Equality Predicates and Hash Functions>> section
for more details.
There are other differences, which are listed in the
<<comparison,Comparison with Associative Containers>> section.
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[#rationale]
:idprefix: rationale_
= Implementation Rationale
The intent of this library is to implement the unordered
containers in the standard, so the interface was fixed. But there are
still some implementation decisions to make. The priorities are
conformance to the standard and portability.
The http://en.wikipedia.org/wiki/Hash_table[Wikipedia article on hash tables^]
has a good summary of the implementation issues for hash tables in general.
== Data Structure
By specifying an interface for accessing the buckets of the container the
standard pretty much requires that the hash table uses chained addressing.
It would be conceivable to write a hash table that uses another method. For
example, it could use open addressing, and use the lookup chain to act as a
bucket but there are some serious problems with this:
* The standard requires that pointers to elements aren't invalidated, so
the elements can't be stored in one array, but will need a layer of
indirection instead - losing the efficiency and most of the memory gain,
the main advantages of open addressing.
* Local iterators would be very inefficient and may not be able to
meet the complexity requirements.
* There are also the restrictions on when iterators can be invalidated. Since
open addressing degrades badly when there are a high number of collisions the
restrictions could prevent a rehash when it's really needed. The maximum load
factor could be set to a fairly low value to work around this - but the
standard requires that it is initially set to 1.0.
* And since the standard is written with a eye towards chained
addressing, users will be surprised if the performance doesn't reflect that.
So chained addressing is used.
== Number of Buckets
There are two popular methods for choosing the number of buckets in a hash
table. One is to have a prime number of buckets, another is to use a power
of 2.
Using a prime number of buckets, and choosing a bucket by using the modulus
of the hash function's result will usually give a good result. The downside
is that the required modulus operation is fairly expensive. This is what the
containers used to do in most cases.
Using a power of 2 allows for much quicker selection of the bucket to use,
but at the expense of losing the upper bits of the hash value. For some
specially designed hash functions it is possible to do this and still get a
good result but as the containers can take arbitrary hash functions this can't
be relied on.
To avoid this a transformation could be applied to the hash function, for an
example see
http://web.archive.org/web/20121102023700/http://www.concentric.net/~Ttwang/tech/inthash.htm[Thomas Wang's article on integer hash functions^].
Unfortunately, a transformation like Wang's requires knowledge of the number
of bits in the hash value, so it was only used when `size_t` was 64 bit.
Since release 1.79.0, https://en.wikipedia.org/wiki/Hash_function#Fibonacci_hashing[Fibonacci hashing]
is used instead. With this implementation, the bucket number is determined
by using `(h * m) >> (w - k)`, where `h` is the hash value, `m` is the golden
ratio multiplied by `2^w`, `w` is the word size (32 or 64), and `2^k` is the
number of buckets. This provides a good compromise between speed and
distribution.
Since release 1.80.0, prime numbers are chosen for the number of buckets in
tandem with sophisticated modulo arithmetic. This removes the need for "mixing"
the result of the user's hash function as was used for release 1.79.0.
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[#reference]
= Reference
include::unordered_map.adoc[]
include::unordered_multimap.adoc[]
include::unordered_set.adoc[]
include::unordered_multiset.adoc[]
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@@ -19,6 +19,7 @@
namespace hash_examples
{
struct iequal_to
: std::binary_function<std::string, std::string, bool>
{
iequal_to() {}
explicit iequal_to(std::locale const& l) : locale_(l) {}
@@ -33,6 +34,7 @@ namespace hash_examples
};
struct ihash
: std::unary_function<std::string, std::size_t>
{
ihash() {}
explicit ihash(std::locale const& l) : locale_(l) {}
+1 -1
View File
@@ -4,7 +4,7 @@
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#include "./case_insensitive.hpp"
#include <boost/core/lightweight_test.hpp>
#include <boost/detail/lightweight_test.hpp>
#include <boost/unordered_map.hpp>
struct word_info {

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